Merge

src/java.base/share/classes/com/sun/crypto/provider/GHASH.java

@@ -124,10 +124,10 @@ final class GHASH {
 
     }
 
-    /* subkeyH and state are stored in long[] for GHASH intrinsic use */
+    /* subkeyHtbl and state are stored in long[] for GHASH intrinsic use */
 
-    // hash subkey H; should not change after the object has been constructed
-    private final long[] subkeyH;
+    // hashtable subkeyHtbl; holds 2*9 powers of subkeyH computed using carry-less multiplication
+    private long[] subkeyHtbl;
 
     // buffer for storing hash
     private final long[] state;
@@ -149,9 +149,9 @@ final class GHASH {
             throw new ProviderException("Internal error");
         }
         state = new long[2];
-        this.subkeyH = new long[2];
-        this.subkeyH[0] = getLong(subkeyH, 0);
-        this.subkeyH[1] = getLong(subkeyH, 8);
+        subkeyHtbl = new long[2*9];
+        subkeyHtbl[0] = getLong(subkeyH, 0);
+        subkeyHtbl[1] = getLong(subkeyH, 8);
     }
 
     /**
@@ -194,8 +194,8 @@ final class GHASH {
         if (inLen == 0) {
             return;
         }
-        ghashRangeCheck(in, inOfs, inLen, state, subkeyH);
-        processBlocks(in, inOfs, inLen/AES_BLOCK_SIZE, state, subkeyH);
+        ghashRangeCheck(in, inOfs, inLen, state, subkeyHtbl);
+        processBlocks(in, inOfs, inLen/AES_BLOCK_SIZE, state, subkeyHtbl);
     }
 
     private static void ghashRangeCheck(byte[] in, int inOfs, int inLen, long[] st, long[] subH) {
@@ -219,8 +219,8 @@ final class GHASH {
             throw new RuntimeException("internal state has invalid length: " +
                                        st.length);
         }
-        if (subH.length != 2) {
-            throw new RuntimeException("internal subkeyH has invalid length: " +
+        if (subH.length != 18) {
+            throw new RuntimeException("internal subkeyHtbl has invalid length: " +
                                        subH.length);
         }
     }

src/java.base/share/classes/com/sun/crypto/provider/HmacPKCS12PBECore.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -26,9 +26,7 @@
 package com.sun.crypto.provider;
 
 import java.util.Arrays;
-import java.nio.ByteBuffer;
 
-import javax.crypto.MacSpi;
 import javax.crypto.SecretKey;
 import javax.crypto.spec.SecretKeySpec;
 import javax.crypto.spec.PBEParameterSpec;
@@ -36,18 +34,65 @@ import java.security.*;
 import java.security.spec.*;
 
 /**
- * This is an implementation of the HMAC-PBESHA1 algorithm as defined
- * in PKCS#12 v1.0 standard.
+ * This is an implementation of the HMAC algorithms as defined
+ * in PKCS#12 v1.1 standard (see RFC 7292 Appendix B.4).
  *
  * @author Valerie Peng
  */
-public final class HmacPKCS12PBESHA1 extends HmacCore {
+abstract class HmacPKCS12PBECore extends HmacCore {
+
+    public static final class HmacPKCS12PBE_SHA1 extends HmacPKCS12PBECore {
+        public HmacPKCS12PBE_SHA1() throws NoSuchAlgorithmException {
+            super("SHA1", 64);
+        }
+    }
+
+    public static final class HmacPKCS12PBE_SHA224 extends HmacPKCS12PBECore {
+        public HmacPKCS12PBE_SHA224() throws NoSuchAlgorithmException {
+            super("SHA-224", 64);
+        }
+    }
+
+    public static final class HmacPKCS12PBE_SHA256 extends HmacPKCS12PBECore {
+        public HmacPKCS12PBE_SHA256() throws NoSuchAlgorithmException {
+            super("SHA-256", 64);
+        }
+    }
+
+    public static final class HmacPKCS12PBE_SHA384 extends HmacPKCS12PBECore {
+        public HmacPKCS12PBE_SHA384() throws NoSuchAlgorithmException {
+            super("SHA-384", 128);
+        }
+    }
+
+    public static final class HmacPKCS12PBE_SHA512 extends HmacPKCS12PBECore {
+        public HmacPKCS12PBE_SHA512() throws NoSuchAlgorithmException {
+            super("SHA-512", 128);
+        }
+    }
+
+    public static final class HmacPKCS12PBE_SHA512_224 extends HmacPKCS12PBECore {
+        public HmacPKCS12PBE_SHA512_224() throws NoSuchAlgorithmException {
+            super("SHA-512/224", 128);
+        }
+    }
+
+    public static final class HmacPKCS12PBE_SHA512_256 extends HmacPKCS12PBECore {
+        public HmacPKCS12PBE_SHA512_256() throws NoSuchAlgorithmException {
+            super("SHA-512/256", 128);
+        }
+    }
+
+    private final String algorithm;
+    private final int bl;
 
     /**
      * Standard constructor, creates a new HmacSHA1 instance.
      */
-    public HmacPKCS12PBESHA1() throws NoSuchAlgorithmException {
-        super("SHA1", 64);
+    public HmacPKCS12PBECore(String algorithm, int bl) throws NoSuchAlgorithmException {
+        super(algorithm, bl);
+        this.algorithm = algorithm;
+        this.bl = bl;
     }
 
     /**
@@ -132,7 +177,8 @@ public final class HmacPKCS12PBESHA1 extends HmacCore {
                         ("IterationCount must be a positive number");
             }
             derivedKey = PKCS12PBECipherCore.derive(passwdChars, salt,
-                    iCount, engineGetMacLength(), PKCS12PBECipherCore.MAC_KEY);
+                    iCount, engineGetMacLength(), PKCS12PBECipherCore.MAC_KEY,
+                    algorithm, bl);
         } finally {
             Arrays.fill(passwdChars, '\0');
         }

src/java.base/share/classes/com/sun/crypto/provider/PBES2Parameters.java

@@ -314,41 +314,48 @@ abstract class PBES2Parameters extends AlgorithmParametersSpi {
                 + "not an ASN.1 OCTET STRING tag");
         }
         iCount = pBKDF2_params.data.getInteger();
+
+        DerValue prf = null;
         // keyLength INTEGER (1..MAX) OPTIONAL,
         if (pBKDF2_params.data.available() > 0) {
             DerValue keyLength = pBKDF2_params.data.getDerValue();
             if (keyLength.tag == DerValue.tag_Integer) {
                 keysize = keyLength.getInteger() * 8; // keysize (in bits)
+            } else {
+                // Should be the prf
+                prf = keyLength;
             }
         }
         // prf AlgorithmIdentifier {{PBKDF2-PRFs}} DEFAULT algid-hmacWithSHA1
         String kdfAlgo = "HmacSHA1";
-        if (pBKDF2_params.data.available() > 0) {
-            if (pBKDF2_params.tag == DerValue.tag_Sequence) {
-                DerValue prf = pBKDF2_params.data.getDerValue();
-                kdfAlgo_OID = prf.data.getOID();
-                if (hmacWithSHA1_OID.equals(kdfAlgo_OID)) {
-                    kdfAlgo = "HmacSHA1";
-                } else if (hmacWithSHA224_OID.equals(kdfAlgo_OID)) {
-                    kdfAlgo = "HmacSHA224";
-                } else if (hmacWithSHA256_OID.equals(kdfAlgo_OID)) {
-                    kdfAlgo = "HmacSHA256";
-                } else if (hmacWithSHA384_OID.equals(kdfAlgo_OID)) {
-                    kdfAlgo = "HmacSHA384";
-                } else if (hmacWithSHA512_OID.equals(kdfAlgo_OID)) {
-                    kdfAlgo = "HmacSHA512";
-                } else {
+        if (prf == null) {
+            if (pBKDF2_params.data.available() > 0) {
+                prf = pBKDF2_params.data.getDerValue();
+            }
+        }
+        if (prf != null) {
+            kdfAlgo_OID = prf.data.getOID();
+            if (hmacWithSHA1_OID.equals(kdfAlgo_OID)) {
+                kdfAlgo = "HmacSHA1";
+            } else if (hmacWithSHA224_OID.equals(kdfAlgo_OID)) {
+                kdfAlgo = "HmacSHA224";
+            } else if (hmacWithSHA256_OID.equals(kdfAlgo_OID)) {
+                kdfAlgo = "HmacSHA256";
+            } else if (hmacWithSHA384_OID.equals(kdfAlgo_OID)) {
+                kdfAlgo = "HmacSHA384";
+            } else if (hmacWithSHA512_OID.equals(kdfAlgo_OID)) {
+                kdfAlgo = "HmacSHA512";
+            } else {
+                throw new IOException("PBE parameter parsing error: "
+                        + "expecting the object identifier for a HmacSHA key "
+                        + "derivation function");
+            }
+            if (prf.data.available() != 0) {
+                // parameter is 'NULL' for all HmacSHA KDFs
+                DerValue parameter = prf.data.getDerValue();
+                if (parameter.tag != DerValue.tag_Null) {
                     throw new IOException("PBE parameter parsing error: "
-                            + "expecting the object identifier for a HmacSHA key "
-                            + "derivation function");
-                }
-                if (prf.data.available() != 0) {
-                    // parameter is 'NULL' for all HmacSHA KDFs
-                    DerValue parameter = prf.data.getDerValue();
-                    if (parameter.tag != DerValue.tag_Null) {
-                        throw new IOException("PBE parameter parsing error: "
-                                + "not an ASN.1 NULL tag");
-                    }
+                            + "not an ASN.1 NULL tag");
                 }
             }
         }

src/java.base/share/classes/com/sun/java/util/jar/pack/Attribute.java

@@ -996,7 +996,7 @@ class Attribute implements Comparable<Attribute> {
                             endp = cstr.indexOf(',', cp);
                             if (endp < 0)  endp = cstrlen;
                             String cstr1 = cstr.substring(cp, endp);
-                            if (cstr1.length() == 0)
+                            if (cstr1.isEmpty())
                                 cstr1 = "empty";  // will fail parse
                             int value0, value1;
                             // Check for a case range (new in 1.6).

src/java.base/share/classes/com/sun/java/util/jar/pack/Constants.java

@@ -50,6 +50,7 @@ class Constants {
         1.10 to 1.10.X 54,0
         1.11 to 1.11.X 55,0
         1.12 to 1.12.X 56,0
+        1.13 to 1.13.X 57,0
     */
 
     public static final Package.Version JAVA_MIN_CLASS_VERSION =
@@ -79,6 +80,9 @@ class Constants {
     public static final Package.Version JAVA12_MAX_CLASS_VERSION =
             Package.Version.of(56, 00);
 
+    public static final Package.Version JAVA13_MAX_CLASS_VERSION =
+            Package.Version.of(57, 00);
+
     public static final int JAVA_PACKAGE_MAGIC = 0xCAFED00D;
 
     public static final Package.Version JAVA5_PACKAGE_VERSION =
@@ -95,7 +99,7 @@ class Constants {
 
     // upper limit, should point to the latest class version
     public static final Package.Version JAVA_MAX_CLASS_VERSION =
-            JAVA12_MAX_CLASS_VERSION;
+            JAVA13_MAX_CLASS_VERSION;
 
     // upper limit should point to the latest package version, for version info!.
     public static final Package.Version MAX_PACKAGE_VERSION =

src/java.base/share/classes/com/sun/java/util/jar/pack/Driver.java

@@ -279,7 +279,7 @@ class Driver {
         junpack.properties().putAll(engProps);
         if (doRepack && newfile.equals(jarfile)) {
             String zipc = getZipComment(jarfile);
-            if (verbose && zipc.length() > 0)
+            if (verbose && !zipc.isEmpty())
                 System.out.println(MessageFormat.format(RESOURCE.getString(DriverResource.DETECTED_ZIP_COMMENT), zipc));
             if (zipc.indexOf(Utils.PACK_ZIP_ARCHIVE_MARKER_COMMENT) >= 0) {
                     System.out.println(MessageFormat.format(RESOURCE.getString(DriverResource.SKIP_FOR_REPACKED), jarfile));
@@ -552,7 +552,7 @@ class Driver {
             if (words.length == 0)    continue loadOptmap;
             String opt = words[0];
             words[0] = "";  // initial word is not a spec
-            if (opt.length() == 0 && words.length >= 1) {
+            if (opt.isEmpty() && words.length >= 1) {
                 opt = words[1];  // initial "word" is empty due to leading ' '
                 words[1] = "";
             }
@@ -622,7 +622,7 @@ class Driver {
                     switch (specop) {
                     case '+':
                         // + means we want an non-empty val suffix.
-                        ok = (val.length() != 0);
+                        ok = !val.isEmpty();
                         specop = spec.charAt(sidx++);
                         break;
                     case '*':
@@ -641,10 +641,10 @@ class Driver {
                     String specarg = spec.substring(sidx);
                     switch (specop) {
                     case '.':  // terminate the option sequence
-                        resultString = (specarg.length() != 0)? specarg.intern(): opt;
+                        resultString = specarg.isEmpty() ? opt : specarg.intern();
                         break doArgs;
                     case '?':  // abort the option sequence
-                        resultString = (specarg.length() != 0)? specarg.intern(): arg;
+                        resultString = specarg.isEmpty() ? arg : specarg.intern();
                         isError = true;
                         break eachSpec;
                     case '@':  // change the effective opt name
@@ -655,14 +655,14 @@ class Driver {
                         val = "";
                         break;
                     case '!':  // negation option
-                        String negopt = (specarg.length() != 0)? specarg.intern(): opt;
+                        String negopt = specarg.isEmpty() ? opt : specarg.intern();
                         properties.remove(negopt);
                         properties.put(negopt, null);  // leave placeholder
                         didAction = true;
                         break;
                     case '$':  // normal "boolean" option
                         String boolval;
-                        if (specarg.length() != 0) {
+                        if (!specarg.isEmpty()) {
                             // If there is a given spec token, store it.
                             boolval = specarg;
                         } else {

src/java.base/share/classes/com/sun/net/ssl/KeyManagerFactory.java

@@ -153,7 +153,7 @@ public class KeyManagerFactory {
                                                  String provider)
         throws NoSuchAlgorithmException, NoSuchProviderException
     {
-        if (provider == null || provider.length() == 0)
+        if (provider == null || provider.isEmpty())
             throw new IllegalArgumentException("missing provider");
         Object[] objs = SSLSecurity.getImpl(algorithm, "KeyManagerFactory",
                                             provider);

src/java.base/share/classes/com/sun/net/ssl/SSLContext.java

@@ -109,7 +109,7 @@ public class SSLContext {
     public static SSLContext getInstance(String protocol, String provider)
         throws NoSuchAlgorithmException, NoSuchProviderException
     {
-        if (provider == null || provider.length() == 0)
+        if (provider == null || provider.isEmpty())
             throw new IllegalArgumentException("missing provider");
         Object[] objs = SSLSecurity.getImpl(protocol, "SSLContext",
                                             provider);

src/java.base/share/classes/com/sun/net/ssl/TrustManagerFactory.java

@@ -155,7 +155,7 @@ public class TrustManagerFactory {
                                                  String provider)
         throws NoSuchAlgorithmException, NoSuchProviderException
     {
-        if (provider == null || provider.length() == 0)
+        if (provider == null || provider.isEmpty())
             throw new IllegalArgumentException("missing provider");
         Object[] objs = SSLSecurity.getImpl(algorithm, "TrustManagerFactory",
                                             provider);

src/java.base/share/classes/java/io/Console.java

@@ -247,7 +247,7 @@ public final class Console implements Flushable
         String line = null;
         synchronized (writeLock) {
             synchronized(readLock) {
-                if (fmt.length() != 0)
+                if (!fmt.isEmpty())
                     pw.format(fmt, args);
                 try {
                     char[] ca = readline(false);
@@ -319,7 +319,7 @@ public final class Console implements Flushable
                 }
                 IOError ioe = null;
                 try {
-                    if (fmt.length() != 0)
+                    if (!fmt.isEmpty())
                         pw.format(fmt, args);
                     passwd = readline(true);
                 } catch (IOException x) {

src/java.base/share/classes/java/io/ObjectStreamClass.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1996, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1996, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -2275,7 +2275,7 @@ public class ObjectStreamClass implements Serializable {
      */
     private static class FieldReflectorKey extends WeakReference<Class<?>> {
 
-        private final String sigs;
+        private final String[] sigs;
         private final int hash;
         private final boolean nullClass;
 
@@ -2284,13 +2284,13 @@ public class ObjectStreamClass implements Serializable {
         {
             super(cl, queue);
             nullClass = (cl == null);
-            StringBuilder sbuf = new StringBuilder();
-            for (int i = 0; i < fields.length; i++) {
+            sigs = new String[2 * fields.length];
+            for (int i = 0, j = 0; i < fields.length; i++) {
                 ObjectStreamField f = fields[i];
-                sbuf.append(f.getName()).append(f.getSignature());
+                sigs[j++] = f.getName();
+                sigs[j++] = f.getSignature();
             }
-            sigs = sbuf.toString();
-            hash = System.identityHashCode(cl) + sigs.hashCode();
+            hash = System.identityHashCode(cl) + Arrays.hashCode(sigs);
         }
 
         public int hashCode() {
@@ -2308,7 +2308,7 @@ public class ObjectStreamClass implements Serializable {
                 return (nullClass ? other.nullClass
                                   : ((referent = get()) != null) &&
                                     (referent == other.get())) &&
-                    sigs.equals(other.sigs);
+                        Arrays.equals(sigs, other.sigs);
             } else {
                 return false;
             }

src/java.base/share/classes/java/io/PrintStream.java

@@ -575,7 +575,7 @@ public class PrintStream extends FilterOutputStream
      * stream occur as promptly as with the original PrintStream.
      */
 
-    private void write(char buf[]) {
+    private void write(char[] buf) {
         try {
             synchronized (this) {
                 ensureOpen();
@@ -584,10 +584,34 @@ public class PrintStream extends FilterOutputStream
                 charOut.flushBuffer();
                 if (autoFlush) {
                     for (int i = 0; i < buf.length; i++)
-                        if (buf[i] == '\n')
+                        if (buf[i] == '\n') {
                             out.flush();
+                            break;
+                        }
                 }
             }
+        } catch (InterruptedIOException x) {
+            Thread.currentThread().interrupt();
+        } catch (IOException x) {
+            trouble = true;
+        }
+    }
+
+    // Used to optimize away back-to-back flushing and synchronization when
+    // using println, but since subclasses could exist which depend on
+    // observing a call to print followed by newLine() we only use this if
+    // getClass() == PrintStream.class to avoid compatibility issues.
+    private void writeln(char[] buf) {
+        try {
+            synchronized (this) {
+                ensureOpen();
+                textOut.write(buf);
+                textOut.newLine();
+                textOut.flushBuffer();
+                charOut.flushBuffer();
+                if (autoFlush)
+                    out.flush();
+            }
         }
         catch (InterruptedIOException x) {
             Thread.currentThread().interrupt();
@@ -616,6 +640,30 @@ public class PrintStream extends FilterOutputStream
         }
     }
 
+    // Used to optimize away back-to-back flushing and synchronization when
+    // using println, but since subclasses could exist which depend on
+    // observing a call to print followed by newLine we only use this if
+    // getClass() == PrintStream.class to avoid compatibility issues.
+    private void writeln(String s) {
+        try {
+            synchronized (this) {
+                ensureOpen();
+                textOut.write(s);
+                textOut.newLine();
+                textOut.flushBuffer();
+                charOut.flushBuffer();
+                if (autoFlush)
+                    out.flush();
+            }
+        }
+        catch (InterruptedIOException x) {
+            Thread.currentThread().interrupt();
+        }
+        catch (IOException x) {
+            trouble = true;
+        }
+    }
+
     private void newLine() {
         try {
             synchronized (this) {
@@ -780,9 +828,13 @@ public class PrintStream extends FilterOutputStream
      * @param x  The {@code boolean} to be printed
      */
     public void println(boolean x) {
-        synchronized (this) {
-            print(x);
-            newLine();
+        if (getClass() == PrintStream.class) {
+            writeln(String.valueOf(x));
+        } else {
+            synchronized (this) {
+                print(x);
+                newLine();
+            }
         }
     }
 
@@ -794,9 +846,13 @@ public class PrintStream extends FilterOutputStream
      * @param x  The {@code char} to be printed.
      */
     public void println(char x) {
-        synchronized (this) {
-            print(x);
-            newLine();
+        if (getClass() == PrintStream.class) {
+            writeln(String.valueOf(x));
+        } else {
+            synchronized (this) {
+                print(x);
+                newLine();
+            }
         }
     }
 
@@ -808,9 +864,13 @@ public class PrintStream extends FilterOutputStream
      * @param x  The {@code int} to be printed.
      */
     public void println(int x) {
-        synchronized (this) {
-            print(x);
-            newLine();
+        if (getClass() == PrintStream.class) {
+            writeln(String.valueOf(x));
+        } else {
+            synchronized (this) {
+                print(x);
+                newLine();
+            }
         }
     }
 
@@ -822,9 +882,13 @@ public class PrintStream extends FilterOutputStream
      * @param x  a The {@code long} to be printed.
      */
     public void println(long x) {
-        synchronized (this) {
-            print(x);
-            newLine();
+        if (getClass() == PrintStream.class) {
+            writeln(String.valueOf(x));
+        } else {
+            synchronized (this) {
+                print(x);
+                newLine();
+            }
         }
     }
 
@@ -836,9 +900,13 @@ public class PrintStream extends FilterOutputStream
      * @param x  The {@code float} to be printed.
      */
     public void println(float x) {
-        synchronized (this) {
-            print(x);
-            newLine();
+        if (getClass() == PrintStream.class) {
+            writeln(String.valueOf(x));
+        } else {
+            synchronized (this) {
+                print(x);
+                newLine();
+            }
         }
     }
 
@@ -850,9 +918,13 @@ public class PrintStream extends FilterOutputStream
      * @param x  The {@code double} to be printed.
      */
     public void println(double x) {
-        synchronized (this) {
-            print(x);
-            newLine();
+        if (getClass() == PrintStream.class) {
+            writeln(String.valueOf(x));
+        } else {
+            synchronized (this) {
+                print(x);
+                newLine();
+            }
         }
     }
 
@@ -863,10 +935,14 @@ public class PrintStream extends FilterOutputStream
      *
      * @param x  an array of chars to print.
      */
-    public void println(char x[]) {
-        synchronized (this) {
-            print(x);
-            newLine();
+    public void println(char[] x) {
+        if (getClass() == PrintStream.class) {
+            writeln(x);
+        } else {
+            synchronized (this) {
+                print(x);
+                newLine();
+            }
         }
     }
 
@@ -878,9 +954,13 @@ public class PrintStream extends FilterOutputStream
      * @param x  The {@code String} to be printed.
      */
     public void println(String x) {
-        synchronized (this) {
-            print(x);
-            newLine();
+        if (getClass() == PrintStream.class) {
+            writeln(String.valueOf(x));
+        } else {
+            synchronized (this) {
+                print(x);
+                newLine();
+            }
         }
     }
 
@@ -895,9 +975,15 @@ public class PrintStream extends FilterOutputStream
      */
     public void println(Object x) {
         String s = String.valueOf(x);
-        synchronized (this) {
-            print(s);
-            newLine();
+        if (getClass() == PrintStream.class) {
+            // need to apply String.valueOf again since first invocation
+            // might return null
+            writeln(String.valueOf(s));
+        } else {
+            synchronized (this) {
+                print(s);
+                newLine();
+            }
         }
     }
 

src/java.base/share/classes/java/lang/Character.java

@@ -9085,7 +9085,7 @@ class Character implements java.io.Serializable, Comparable<Character> {
      * @since   1.5
      */
     public static boolean isLowerCase(int codePoint) {
-        return getType(codePoint) == Character.LOWERCASE_LETTER ||
+        return CharacterData.of(codePoint).isLowerCase(codePoint) ||
                CharacterData.of(codePoint).isOtherLowercase(codePoint);
     }
 
@@ -9151,7 +9151,7 @@ class Character implements java.io.Serializable, Comparable<Character> {
      * @since   1.5
      */
     public static boolean isUpperCase(int codePoint) {
-        return getType(codePoint) == Character.UPPERCASE_LETTER ||
+        return CharacterData.of(codePoint).isUpperCase(codePoint) ||
                CharacterData.of(codePoint).isOtherUppercase(codePoint);
     }
 
@@ -9302,7 +9302,7 @@ class Character implements java.io.Serializable, Comparable<Character> {
      * @since   1.5
      */
     public static boolean isDigit(int codePoint) {
-        return getType(codePoint) == Character.DECIMAL_DIGIT_NUMBER;
+        return CharacterData.of(codePoint).isDigit(codePoint);
     }
 
     /**

src/java.base/share/classes/java/lang/CharacterData.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2006, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2006, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,6 +28,9 @@ package java.lang;
 abstract class CharacterData {
     abstract int getProperties(int ch);
     abstract int getType(int ch);
+    abstract boolean isDigit(int ch);
+    abstract boolean isLowerCase(int ch);
+    abstract boolean isUpperCase(int ch);
     abstract boolean isWhitespace(int ch);
     abstract boolean isMirrored(int ch);
     abstract boolean isJavaIdentifierStart(int ch);

src/java.base/share/classes/java/lang/ClassLoader.java

@@ -1119,7 +1119,7 @@ public abstract class ClassLoader {
 
     // true if the name is null or has the potential to be a valid binary name
     private boolean checkName(String name) {
-        if ((name == null) || (name.length() == 0))
+        if ((name == null) || (name.isEmpty()))
             return true;
         if ((name.indexOf('/') != -1) || (name.charAt(0) == '['))
             return false;
@@ -1864,12 +1864,12 @@ public abstract class ClassLoader {
      * <p> The default system class loader is an implementation-dependent
      * instance of this class.
      *
-     * <p> If the system property "{@code java.system.class.loader}" is defined
-     * when this method is first invoked then the value of that property is
-     * taken to be the name of a class that will be returned as the system
-     * class loader.  The class is loaded using the default system class loader
-     * and must define a public constructor that takes a single parameter of
-     * type {@code ClassLoader} which is used as the delegation parent.  An
+     * <p> If the system property "{@systemProperty java.system.class.loader}"
+     * is defined when this method is first invoked then the value of that
+     * property is taken to be the name of a class that will be returned as the
+     * system class loader. The class is loaded using the default system class
+     * loader and must define a public constructor that takes a single parameter
+     * of type {@code ClassLoader} which is used as the delegation parent. An
      * instance is then created using this constructor with the default system
      * class loader as the parameter.  The resulting class loader is defined
      * to be the system class loader. During construction, the class loader

src/java.base/share/classes/java/lang/Double.java

@@ -1077,8 +1077,8 @@ public final class Double extends Number
     }
 
     /**
-     * Returns a nominal descriptor for this instance, which is the instance
-     * itself.
+     * Returns an {@link Optional} containing the nominal descriptor for this
+     * instance, which is the instance itself.
      *
      * @return an {@link Optional} describing the {@linkplain Double} instance
      * @since 12

src/java.base/share/classes/java/lang/Float.java

@@ -989,8 +989,8 @@ public final class Float extends Number
     }
 
     /**
-     * Returns a nominal descriptor for this instance, which is the instance
-     * itself.
+     * Returns an {@link Optional} containing the nominal descriptor for this
+     * instance, which is the instance itself.
      *
      * @return an {@link Optional} describing the {@linkplain Float} instance
      * @since 12

src/java.base/share/classes/java/lang/Integer.java

@@ -1409,7 +1409,7 @@ public final class Integer extends Number
         boolean negative = false;
         Integer result;
 
-        if (nm.length() == 0)
+        if (nm.isEmpty())
             throw new NumberFormatException("Zero length string");
         char firstChar = nm.charAt(0);
         // Handle sign, if present
@@ -1838,8 +1838,8 @@ public final class Integer extends Number
     }
 
     /**
-     * Returns a nominal descriptor for this instance, which is the instance
-     * itself.
+     * Returns an {@link Optional} containing the nominal descriptor for this
+     * instance, which is the instance itself.
      *
      * @return an {@link Optional} describing the {@linkplain Integer} instance
      * @since 12

src/java.base/share/classes/java/lang/Long.java

@@ -1248,7 +1248,7 @@ public final class Long extends Number
         boolean negative = false;
         Long result;
 
-        if (nm.length() == 0)
+        if (nm.isEmpty())
             throw new NumberFormatException("Zero length string");
         char firstChar = nm.charAt(0);
         // Handle sign, if present
@@ -1967,8 +1967,8 @@ public final class Long extends Number
     }
 
     /**
-     * Returns a nominal descriptor for this instance, which is the instance
-     * itself.
+     * Returns an {@link Optional} containing the nominal descriptor for this
+     * instance, which is the instance itself.
      *
      * @return an {@link Optional} describing the {@linkplain Long} instance
      * @since 12

src/java.base/share/classes/java/lang/Math.java

@@ -1460,6 +1460,7 @@ public final class Math {
      * @param   b   another argument.
      * @return  the larger of {@code a} and {@code b}.
      */
+    @HotSpotIntrinsicCandidate
     public static float max(float a, float b) {
         if (a != a)
             return a;   // a is NaN
@@ -1486,6 +1487,7 @@ public final class Math {
      * @param   b   another argument.
      * @return  the larger of {@code a} and {@code b}.
      */
+    @HotSpotIntrinsicCandidate
     public static double max(double a, double b) {
         if (a != a)
             return a;   // a is NaN
@@ -1541,6 +1543,7 @@ public final class Math {
      * @param   b   another argument.
      * @return  the smaller of {@code a} and {@code b}.
      */
+    @HotSpotIntrinsicCandidate
     public static float min(float a, float b) {
         if (a != a)
             return a;   // a is NaN
@@ -1567,6 +1570,7 @@ public final class Math {
      * @param   b   another argument.
      * @return  the smaller of {@code a} and {@code b}.
      */
+    @HotSpotIntrinsicCandidate
     public static double min(double a, double b) {
         if (a != a)
             return a;   // a is NaN

src/java.base/share/classes/java/lang/Package.java

@@ -397,11 +397,11 @@ public class Package extends NamedPackage implements java.lang.reflect.Annotated
     public String toString() {
         String spec = versionInfo.specTitle;
         String ver =  versionInfo.specVersion;
-        if (spec != null && spec.length() > 0)
+        if (spec != null && !spec.isEmpty())
             spec = ", " + spec;
         else
             spec = "";
-        if (ver != null && ver.length() > 0)
+        if (ver != null && !ver.isEmpty())
             ver = ", version " + ver;
         else
             ver = "";

src/java.base/share/classes/java/lang/Runtime.java

@@ -403,7 +403,7 @@ public class Runtime {
      */
     public Process exec(String command, String[] envp, File dir)
         throws IOException {
-        if (command.length() == 0)
+        if (command.isEmpty())
             throw new IllegalArgumentException("Empty command");
 
         StringTokenizer st = new StringTokenizer(command);

src/java.base/share/classes/java/lang/StrictMath.java

@@ -1154,6 +1154,7 @@ public final class StrictMath {
      * @param   b   another argument.
      * @return  the larger of {@code a} and {@code b}.
      */
+    @HotSpotIntrinsicCandidate
     public static float max(float a, float b) {
         return Math.max(a, b);
     }
@@ -1172,6 +1173,7 @@ public final class StrictMath {
      * @param   b   another argument.
      * @return  the larger of {@code a} and {@code b}.
      */
+    @HotSpotIntrinsicCandidate
     public static double max(double a, double b) {
         return Math.max(a, b);
     }
@@ -1219,6 +1221,7 @@ public final class StrictMath {
      * @param   b   another argument.
      * @return  the smaller of {@code a} and {@code b.}
      */
+    @HotSpotIntrinsicCandidate
     public static float min(float a, float b) {
         return Math.min(a, b);
     }
@@ -1237,6 +1240,7 @@ public final class StrictMath {
      * @param   b   another argument.
      * @return  the smaller of {@code a} and {@code b}.
      */
+    @HotSpotIntrinsicCandidate
     public static double min(double a, double b) {
         return Math.min(a, b);
     }

src/java.base/share/classes/java/lang/String.java

@@ -1943,8 +1943,7 @@ public final class String
      *          characters followed by the string argument's characters.
      */
     public String concat(String str) {
-        int olen = str.length();
-        if (olen == 0) {
+        if (str.isEmpty()) {
             return this;
         }
         if (coder() == str.coder()) {
@@ -1956,6 +1955,7 @@ public final class String
             return new String(buf, coder);
         }
         int len = length();
+        int olen = str.length();
         byte[] buf = StringUTF16.newBytesFor(len + olen);
         getBytes(buf, 0, UTF16);
         str.getBytes(buf, len, UTF16);
@@ -2316,7 +2316,7 @@ public final class String
             // Construct result
             int resultSize = list.size();
             if (limit == 0) {
-                while (resultSize > 0 && list.get(resultSize - 1).length() == 0) {
+                while (resultSize > 0 && list.get(resultSize - 1).isEmpty()) {
                     resultSize--;
                 }
             }
@@ -3545,8 +3545,8 @@ public final class String
     }
 
     /**
-     * Returns a nominal descriptor for this instance, which is the instance
-     * itself.
+     * Returns an {@link Optional} containing the nominal descriptor for this
+     * instance, which is the instance itself.
      *
      * @return an {@link Optional} describing the {@linkplain String} instance
      * @since 12

src/java.base/share/classes/java/lang/System.java

@@ -801,8 +801,9 @@ public final class System {
         }
 
         if (props == null) {
-            props = SystemProps.initProperties();
-            VersionProps.init(props);
+            Map<String, String> tempProps = SystemProps.initProperties();
+            VersionProps.init(tempProps);
+            props = createProperties(tempProps);
         }
         System.props = props;
     }
@@ -1959,18 +1960,42 @@ public final class System {
         }
     }
 
+    /**
+     * Create the Properties object from a map - masking out system properties
+     * that are not intended for public access.
+     */
+    private static Properties createProperties(Map<String, String> initialProps) {
+        Properties properties = new Properties(initialProps.size());
+        for (var entry : initialProps.entrySet()) {
+            String prop = entry.getKey();
+            switch (prop) {
+                // Do not add private system properties to the Properties
+                case "sun.nio.MaxDirectMemorySize":
+                case "sun.nio.PageAlignDirectMemory":
+                    // used by java.lang.Integer.IntegerCache
+                case "java.lang.Integer.IntegerCache.high":
+                    // used by sun.launcher.LauncherHelper
+                case "sun.java.launcher.diag":
+                    // used by jdk.internal.loader.ClassLoaders
+                case "jdk.boot.class.path.append":
+                    break;
+                default:
+                    properties.put(prop, entry.getValue());
+            }
+        }
+        return properties;
+    }
+
     /**
      * Initialize the system class.  Called after thread initialization.
      */
     private static void initPhase1() {
-
         // VM might invoke JNU_NewStringPlatform() to set those encoding
         // sensitive properties (user.home, user.name, boot.class.path, etc.)
         // during "props" initialization.
         // The charset is initialized in System.c and does not depend on the Properties.
-        props = SystemProps.initProperties();
-        VersionProps.init(props);
-        StaticProperty.javaHome();          // Load StaticProperty to cache the property values
+        Map<String, String> tempProps = SystemProps.initProperties();
+        VersionProps.init(tempProps);
 
         // There are certain system configurations that may be controlled by
         // VM options such as the maximum amount of direct memory and
@@ -1978,15 +2003,14 @@ public final class System {
         // of autoboxing.  Typically, the library will obtain these values
         // from the properties set by the VM.  If the properties are for
         // internal implementation use only, these properties should be
-        // removed from the system properties.
-        //
-        // See java.lang.Integer.IntegerCache and the
-        // VM.saveAndRemoveProperties method for example.
+        // masked from the system properties.
         //
         // Save a private copy of the system properties object that
-        // can only be accessed by the internal implementation.  Remove
-        // certain system properties that are not intended for public access.
-        VM.saveAndRemoveProperties(props);
+        // can only be accessed by the internal implementation.
+        VM.saveProperties(tempProps);
+        props = createProperties(tempProps);
+
+        StaticProperty.javaHome();          // Load StaticProperty to cache the property values
 
         lineSeparator = props.getProperty("line.separator");
 

src/java.base/share/classes/java/lang/VersionProps.java.template

@@ -28,8 +28,8 @@ package java.lang;
 import java.io.PrintStream;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Map;
 import java.util.Optional;
-import java.util.Properties;
 
 class VersionProps {
 
@@ -73,7 +73,7 @@ class VersionProps {
         "@@VENDOR_VERSION_STRING@@";
 
     private static final String vendor_version =
-        (VENDOR_VERSION_STRING.length() > 0
+        (!VENDOR_VERSION_STRING.isEmpty()
          ? " " + VENDOR_VERSION_STRING : "");
 
     private static final String VENDOR =
@@ -88,25 +88,25 @@ class VersionProps {
     /**
      * Initialize system properties using build provided values.
      *
-     * @param props Properties instance in which to insert the properties
+     * @param props Map instance in which to insert the properties
      */
-    public static void init(Properties props) {
-        props.setProperty("java.version", java_version);
-        props.setProperty("java.version.date", java_version_date);
-        props.setProperty("java.runtime.version", java_runtime_version);
-        props.setProperty("java.runtime.name", java_runtime_name);
-        if (VENDOR_VERSION_STRING.length() > 0)
-            props.setProperty("java.vendor.version", VENDOR_VERSION_STRING);
+    public static void init(Map<String, String> props) {
+        props.put("java.version", java_version);
+        props.put("java.version.date", java_version_date);
+        props.put("java.runtime.version", java_runtime_version);
+        props.put("java.runtime.name", java_runtime_name);
+        if (!VENDOR_VERSION_STRING.isEmpty())
+            props.put("java.vendor.version", VENDOR_VERSION_STRING);
 
-        props.setProperty("java.class.version", CLASSFILE_MAJOR_MINOR);
+        props.put("java.class.version", CLASSFILE_MAJOR_MINOR);
 
-        props.setProperty("java.specification.version", VERSION_SPECIFICATION);
-        props.setProperty("java.specification.name", "Java Platform API Specification");
-        props.setProperty("java.specification.vendor", "Oracle Corporation");
+        props.put("java.specification.version", VERSION_SPECIFICATION);
+        props.put("java.specification.name", "Java Platform API Specification");
+        props.put("java.specification.vendor", "Oracle Corporation");
 
-        props.setProperty("java.vendor", VENDOR);
-        props.setProperty("java.vendor.url", VENDOR_URL);
-        props.setProperty("java.vendor.url.bug", VENDOR_URL_BUG);
+        props.put("java.vendor", VENDOR);
+        props.put("java.vendor.url", VENDOR_URL);
+        props.put("java.vendor.url.bug", VENDOR_URL_BUG);
     }
 
     private static int parseVersionNumber(String version, int prevIndex, int index) {

src/java.base/share/classes/java/lang/constant/ClassDesc.java

@@ -112,13 +112,13 @@ public interface ClassDesc
      *
      * A field type descriptor string for a non-array type is either
      * a one-letter code corresponding to a primitive type
-     * ({@code J,I,C,S,B,D,F,Z,V}), or the letter {@code L}, followed
-     * by the fully qualified binary name of a class, followed by {@code ;}.
-     * A field type descriptor for an array type is the character {@code [}
+     * ({@code "J", "I", "C", "S", "B", "D", "F", "Z", "V"}), or the letter {@code "L"}, followed
+     * by the fully qualified binary name of a class, followed by {@code ";"}.
+     * A field type descriptor for an array type is the character {@code "["}
      * followed by the field descriptor for the component type.  Examples of
-     * valid type descriptor strings include {@code Ljava/lang/String;}, {@code I},
-     * {@code [I}, {@code V}, {@code [Ljava/lang/String;}, etc.
-     * for more detail.
+     * valid type descriptor strings include {@code "Ljava/lang/String;"}, {@code "I"},
+     * {@code "[I"}, {@code "V"}, {@code "[Ljava/lang/String;"}, etc.
+     * See JVMS 4.3.2 ("Field Descriptors") for more detail.
      *
      * @param descriptor a field descriptor string
      * @return a {@linkplain ClassDesc} describing the desired class
@@ -126,9 +126,15 @@ public interface ClassDesc
      * @throws IllegalArgumentException if the name string is not in the
      * correct format
      * @jvms 4.3.2 Field Descriptors
+     * @jvms 4.4.1 The CONSTANT_Class_info Structure
      */
     static ClassDesc ofDescriptor(String descriptor) {
         requireNonNull(descriptor);
+        int depth = ConstantUtils.arrayDepth(descriptor);
+        if (depth > ConstantUtils.MAX_ARRAY_TYPE_DESC_DIMENSIONS) {
+            throw new IllegalArgumentException(String.format("Cannot create an array type descriptor with more than %d dimensions",
+                    ConstantUtils.MAX_ARRAY_TYPE_DESC_DIMENSIONS));
+        }
         return (descriptor.length() == 1)
                ? new PrimitiveClassDescImpl(descriptor)
                : new ReferenceClassDescImpl(descriptor);
@@ -139,8 +145,15 @@ public interface ClassDesc
      * is described by this {@linkplain ClassDesc}.
      *
      * @return a {@linkplain ClassDesc} describing the array type
+     * @throws IllegalStateException if the resulting {@linkplain ClassDesc} would have an array rank of greater than 255
+     * @jvms 4.4.1 The CONSTANT_Class_info Structure
      */
     default ClassDesc arrayType() {
+        int depth = ConstantUtils.arrayDepth(descriptorString());
+        if (depth >= ConstantUtils.MAX_ARRAY_TYPE_DESC_DIMENSIONS) {
+            throw new IllegalStateException(String.format("Cannot create an array type descriptor with more than %d dimensions",
+                    ConstantUtils.MAX_ARRAY_TYPE_DESC_DIMENSIONS));
+        }
         return arrayType(1);
     }
 
@@ -150,11 +163,14 @@ public interface ClassDesc
      *
      * @param rank the rank of the array
      * @return a {@linkplain ClassDesc} describing the array type
-     * @throws IllegalArgumentException if the rank is zero or negative
+     * @throws IllegalArgumentException if the rank is less than zero or if the rank of the resulting array type is
+     * greater than 255
+     * @jvms 4.4.1 The CONSTANT_Class_info Structure
      */
     default ClassDesc arrayType(int rank) {
-        if (rank <= 0)
-            throw new IllegalArgumentException("rank: " + rank);
+        int currentDepth = ConstantUtils.arrayDepth(descriptorString());
+        if (rank <= 0 || currentDepth + rank > ConstantUtils.MAX_ARRAY_TYPE_DESC_DIMENSIONS)
+            throw new IllegalArgumentException("rank: " + currentDepth + rank);
         return ClassDesc.ofDescriptor("[".repeat(rank) + descriptorString());
     }
 
@@ -162,6 +178,12 @@ public interface ClassDesc
      * Returns a {@linkplain ClassDesc} for a nested class of the class or
      * interface type described by this {@linkplain ClassDesc}.
      *
+     * @apiNote
+     *
+     * Example: If descriptor {@code d} describes the class {@code java.util.Map}, a
+     * descriptor for the class {@code java.util.Map.Entry} could be obtained
+     * by {@code d.nested("Entry")}.
+     *
      * @param nestedName the unqualified name of the nested class
      * @return a {@linkplain ClassDesc} describing the nested class
      * @throws NullPointerException if any argument is {@code null}

src/java.base/share/classes/java/lang/constant/Constable.java

@@ -65,8 +65,9 @@ import java.util.Optional;
  */
 public interface Constable {
     /**
-     * Returns a nominal descriptor for this instance, if one can be
-     * constructed, or an empty {@link Optional} if one cannot be constructed.
+     * Returns an {@link Optional} containing the nominal descriptor for this
+     * instance, if one can be constructed, or an empty {@link Optional}
+     * if one cannot be constructed.
      *
      * @return An {@link Optional} containing the resulting nominal descriptor,
      * or an empty {@link Optional} if one cannot be constructed.

src/java.base/share/classes/java/lang/constant/ConstantUtils.java

@@ -37,6 +37,7 @@ class ConstantUtils {
     /** an empty constant descriptor */
     public static final ConstantDesc[] EMPTY_CONSTANTDESC = new ConstantDesc[0];
     static final Constable[] EMPTY_CONSTABLE = new Constable[0];
+    static final int MAX_ARRAY_TYPE_DESC_DIMENSIONS = 255;
 
     private static final Set<String> pointyNames = Set.of("<init>", "<clinit>");
 

src/java.base/share/classes/java/lang/constant/package-info.java

@@ -49,7 +49,7 @@
  * storing the value in a constant pool entry, or reconstituting the value given
  * a class loading context.  Every {@link java.lang.constant.ConstantDesc}
  * knows how to <em>resolve</em> itself -- compute the value that it describes --
- * via {@link java.lang.constant.ConstantDesc#resolveConstantDesc(java.lang.invoke.MethodHandles.Lookup)}.
+ * via {@link java.lang.constant.ConstantDesc#resolveConstantDesc(java.lang.invoke.MethodHandles.Lookup) ConstantDesc.resolveConstantDesc}.
  * This allows an API which accepts {@link java.lang.constant.ConstantDesc}
  * objects to evaluate them reflectively, provided that the classes and methods
  * referenced in their nominal description are present and accessible.
@@ -68,7 +68,7 @@
  * When a bytecode-reading API encounters a constant pool entry, it can
  * convert it to the appropriate type of nominal descriptor.  For dynamic
  * constants, bytecode-reading APIs may wish to use the factory
- * {@link java.lang.constant.DynamicConstantDesc#ofCanonical(DirectMethodHandleDesc, java.lang.String, ClassDesc, ConstantDesc[])},
+ * {@link java.lang.constant.DynamicConstantDesc#ofCanonical(DirectMethodHandleDesc, java.lang.String, ClassDesc, ConstantDesc[]) DynamicConstantDesc.ofCanonical},
  * which will inspect the bootstrap and, for well-known bootstraps, return
  * a more specific subtype of {@link java.lang.constant.DynamicConstantDesc}, such as
  * {@link java.lang.Enum.EnumDesc}.

src/java.base/share/classes/java/lang/invoke/ConstantBootstraps.java

@@ -103,7 +103,7 @@ public final class ConstantBootstraps {
         if (type != Class.class) {
             throw new IllegalArgumentException();
         }
-        if (name.length() == 0 || name.length() > 1) {
+        if (name.length() != 1) {
             throw new IllegalArgumentException(String.format("not primitive: %s", name));
         }
 

src/java.base/share/classes/java/lang/invoke/MethodHandles.java

@@ -201,7 +201,7 @@ public class MethodHandles {
             throw new IllegalAccessException(callerModule + " does not read " + targetModule);
         if (targetModule.isNamed()) {
             String pn = targetClass.getPackageName();
-            assert pn.length() > 0 : "unnamed package cannot be in named module";
+            assert !pn.isEmpty() : "unnamed package cannot be in named module";
             if (!targetModule.isOpen(pn, callerModule))
                 throw new IllegalAccessException(targetModule + " does not open " + pn + " to " + callerModule);
         }

src/java.base/share/classes/java/lang/invoke/ProxyClassesDumper.java

@@ -62,7 +62,7 @@ final class ProxyClassesDumper {
         }
         try {
             path = path.trim();
-            final Path dir = Path.of(path.length() == 0 ? "." : path);
+            final Path dir = Path.of(path.isEmpty() ? "." : path);
             AccessController.doPrivileged(new PrivilegedAction<>() {
                     @Override
                     public Void run() {

src/java.base/share/classes/java/lang/invoke/TypeDescriptor.java

@@ -61,7 +61,8 @@ public interface TypeDescriptor {
         boolean isArray();
 
         /**
-         * Does this field descriptor describe a primitive type?
+         * Does this field descriptor describe a primitive type (including void.)
+         *
          * @return whether this field descriptor describes a primitive type
          */
         boolean isPrimitive();

src/java.base/share/classes/java/lang/invoke/VarHandle.java

@@ -1864,6 +1864,16 @@ public abstract class VarHandle implements Constable {
         }
     }
 
+    /**
+     * Compare this {@linkplain VarHandle} with another object for equality.
+     * Two {@linkplain VarHandle}s are considered equal if they both describe the
+     * same instance field, both describe the same static field, both describe
+     * array elements for arrays with the same component type, or both describe
+     * the same component of an off-heap structure.
+     *
+     * @param o the other object
+     * @return Whether this {@linkplain VarHandle} is equal to the other object
+     */
     @Override
     public final boolean equals(Object o) {
         if (this == o) return true;
@@ -1883,6 +1893,12 @@ public abstract class VarHandle implements Constable {
 
     abstract int internalHashCode();
 
+    /**
+     * Returns a compact textual description of this {@linkplain VarHandle},
+     * including the type of variable described, and a description of its coordinates.
+     *
+     * @return A compact textual description of this {@linkplain VarHandle}
+     */
     @Override
     public final String toString() {
         return String.format("VarHandle[varType=%s, coord=%s]",
@@ -2272,6 +2288,14 @@ public abstract class VarHandle implements Constable {
             }
         }
 
+        /**
+         * Returns a compact textual description of this constant description.
+         * For a field {@linkplain VarHandle}, includes the owner, name, and type
+         * of the field, and whether it is static; for an array {@linkplain VarHandle},
+         * the name of the component type.
+         *
+         * @return A compact textual description of this descriptor
+         */
         @Override
         public String toString() {
             switch (kind) {

src/java.base/share/classes/java/math/BigDecimal.java

@@ -2871,6 +2871,8 @@ public class BigDecimal extends Number implements Comparable<BigDecimal> {
      * @throws ArithmeticException if scale overflows.
      */
     public BigDecimal movePointLeft(int n) {
+        if (n == 0) return this;
+
         // Cannot use movePointRight(-n) in case of n==Integer.MIN_VALUE
         int newScale = checkScale((long)scale + n);
         BigDecimal num = new BigDecimal(intVal, intCompact, newScale, 0);
@@ -2893,6 +2895,8 @@ public class BigDecimal extends Number implements Comparable<BigDecimal> {
      * @throws ArithmeticException if scale overflows.
      */
     public BigDecimal movePointRight(int n) {
+        if (n == 0) return this;
+
         // Cannot use movePointLeft(-n) in case of n==Integer.MIN_VALUE
         int newScale = checkScale((long)scale - n);
         BigDecimal num = new BigDecimal(intVal, intCompact, newScale, 0);

src/java.base/share/classes/java/net/DatagramPacket.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1995, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -102,7 +102,7 @@ class DatagramPacket {
 
     /**
      * Constructs a datagram packet for sending packets of length
-     * {@code length} with offset {@code ioffset}to the
+     * {@code length} with offset {@code offset} to the
      * specified port number on the specified host. The
      * {@code length} argument must be less than or equal to
      * {@code buf.length}.
@@ -125,7 +125,7 @@ class DatagramPacket {
 
     /**
      * Constructs a datagram packet for sending packets of length
-     * {@code length} with offset {@code ioffset}to the
+     * {@code length} with offset {@code offset} to the
      * specified port number on the specified host. The
      * {@code length} argument must be less than or equal to
      * {@code buf.length}.

src/java.base/share/classes/java/net/HttpCookie.java

@@ -149,7 +149,7 @@ public final class HttpCookie implements Cloneable {
      */
     HttpCookie(String name, String value, String header, long creationTime) {
         name = name.trim();
-        if (name.length() == 0 || !isToken(name) || name.charAt(0) == '$') {
+        if (name.isEmpty() || !isToken(name) || name.charAt(0) == '$') {
             throw new IllegalArgumentException("Illegal cookie name");
         }
 

src/java.base/share/classes/java/net/Inet6Address.java

@@ -433,7 +433,7 @@ class Inet6Address extends InetAddress {
                                             NetworkInterface nif)
         throws UnknownHostException
     {
-        if (host != null && host.length() > 0 && host.charAt(0) == '[') {
+        if (host != null && !host.isEmpty() && host.charAt(0) == '[') {
             if (host.charAt(host.length()-1) == ']') {
                 host = host.substring(1, host.length() -1);
             }
@@ -466,7 +466,7 @@ class Inet6Address extends InetAddress {
                                             int scope_id)
         throws UnknownHostException
     {
-        if (host != null && host.length() > 0 && host.charAt(0) == '[') {
+        if (host != null && !host.isEmpty() && host.charAt(0) == '[') {
             if (host.charAt(host.length()-1) == ']') {
                 host = host.substring(1, host.length() -1);
             }
@@ -601,7 +601,7 @@ class Inet6Address extends InetAddress {
         boolean scope_ifname_set = gf.get("scope_ifname_set", false);
         String ifname = (String)gf.get("ifname", null);
 
-        if (ifname != null && !"".equals (ifname)) {
+        if (ifname != null && !ifname.isEmpty()) {
             try {
                 scope_ifname = NetworkInterface.getByName(ifname);
                 if (scope_ifname == null) {

src/java.base/share/classes/java/net/InetAddress.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1995, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1995, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -531,7 +531,7 @@ class InetAddress implements java.io.Serializable {
      * @param   timeout the time, in milliseconds, before the call aborts
      * @throws  IllegalArgumentException if either {@code timeout}
      *                          or {@code ttl} are negative.
-     * @return a {@code boolean}indicating if the address is reachable.
+     * @return a {@code boolean} indicating if the address is reachable.
      * @throws IOException if a network error occurs
      * @since 1.5
      */
@@ -1187,7 +1187,7 @@ class InetAddress implements java.io.Serializable {
      */
     public static InetAddress getByAddress(String host, byte[] addr)
         throws UnknownHostException {
-        if (host != null && host.length() > 0 && host.charAt(0) == '[') {
+        if (host != null && !host.isEmpty() && host.charAt(0) == '[') {
             if (host.charAt(host.length()-1) == ']') {
                 host = host.substring(1, host.length() -1);
             }
@@ -1301,7 +1301,7 @@ class InetAddress implements java.io.Serializable {
     private static InetAddress[] getAllByName(String host, InetAddress reqAddr)
         throws UnknownHostException {
 
-        if (host == null || host.length() == 0) {
+        if (host == null || host.isEmpty()) {
             InetAddress[] ret = new InetAddress[1];
             ret[0] = impl.loopbackAddress();
             return ret;

src/java.base/share/classes/java/net/Socket.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1995, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1995, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -1102,7 +1102,7 @@ class Socket implements java.io.Closeable {
      * Tests if {@link SocketOptions#SO_OOBINLINE SO_OOBINLINE} is enabled.
      *
      * @return a {@code boolean} indicating whether or not
-     *         {@link SocketOptions#SO_OOBINLINE SO_OOBINLINE}is enabled.
+     *         {@link SocketOptions#SO_OOBINLINE SO_OOBINLINE} is enabled.
      *
      * @exception SocketException if there is an error
      * in the underlying protocol, such as a TCP error.

src/java.base/share/classes/java/net/SocketPermission.java

@@ -460,7 +460,7 @@ public final class SocketPermission extends Permission
             }
             return;
         } else {
-            if (host.length() > 0) {
+            if (!host.isEmpty()) {
                 // see if we are being initialized with an IP address.
                 char ch = host.charAt(0);
                 if (ch == ':' || Character.digit(ch, 16) != -1) {
@@ -705,8 +705,7 @@ public final class SocketPermission extends Permission
                                       .orElse(b);
         }
 
-        return cdomain.length() != 0 && hdomain.length() != 0
-                        && cdomain.equals(hdomain);
+        return !cdomain.isEmpty() && !hdomain.isEmpty() && cdomain.equals(hdomain);
     }
 
     private boolean authorized(String cname, byte[] addr) {

src/java.base/share/classes/java/net/URI.java

@@ -1959,10 +1959,8 @@ public final class URI
         throws URISyntaxException
     {
         if (scheme != null) {
-            if ((path != null)
-                && ((path.length() > 0) && (path.charAt(0) != '/')))
-                throw new URISyntaxException(s,
-                                             "Relative path in absolute URI");
+            if (path != null && !path.isEmpty() && path.charAt(0) != '/')
+                throw new URISyntaxException(s, "Relative path in absolute URI");
         }
     }
 
@@ -2163,7 +2161,7 @@ public final class URI
             ru.port = base.port;
 
             String cp = (child.path == null) ? "" : child.path;
-            if ((cp.length() > 0) && (cp.charAt(0) == '/')) {
+            if (!cp.isEmpty() && cp.charAt(0) == '/') {
                 // 5.2 (5): Child path is absolute
                 ru.path = child.path;
             } else {
@@ -2187,7 +2185,7 @@ public final class URI
     // o.w., return a new URI containing the normalized path.
     //
     private static URI normalize(URI u) {
-        if (u.isOpaque() || (u.path == null) || (u.path.length() == 0))
+        if (u.isOpaque() || u.path == null || u.path.isEmpty())
             return u;
 
         String np = normalize(u.path);

src/java.base/share/classes/java/net/URL.java

@@ -304,7 +304,7 @@ public final class URL implements java.io.Serializable {
      *     or all providers have been exhausted.
      * <li>If the previous step fails to find a protocol handler, the
      *     constructor reads the value of the system property:
-     *     <blockquote>{@code
+     *     <blockquote>{@systemProperty
      *         java.protocol.handler.pkgs
      *     }</blockquote>
      *     If the value of that system property is not {@code null},
@@ -1220,16 +1220,22 @@ public final class URL implements java.io.Serializable {
     private static final URLStreamHandlerFactory defaultFactory = new DefaultFactory();
 
     private static class DefaultFactory implements URLStreamHandlerFactory {
-        private static String PREFIX = "sun.net.www.protocol";
+        private static String PREFIX = "sun.net.www.protocol.";
 
         public URLStreamHandler createURLStreamHandler(String protocol) {
-            String name = PREFIX + "." + protocol + ".Handler";
+            // Avoid using reflection during bootstrap
+            switch (protocol) {
+                case "file":
+                    return new sun.net.www.protocol.file.Handler();
+                case "jar":
+                    return new sun.net.www.protocol.jar.Handler();
+                case "jrt":
+                    return new sun.net.www.protocol.jrt.Handler();
+            }
+            String name = PREFIX + protocol + ".Handler";
             try {
-                @SuppressWarnings("deprecation")
-                Object o = Class.forName(name).newInstance();
+                Object o = Class.forName(name).getDeclaredConstructor().newInstance();
                 return (URLStreamHandler)o;
-            } catch (ClassNotFoundException x) {
-                // ignore
             } catch (Exception e) {
                 // For compatibility, all Exceptions are ignored.
                 // any number of exceptions can get thrown here
@@ -1513,7 +1519,7 @@ public final class URL implements java.io.Serializable {
         String ref = (String)gf.get("ref", null);
         int hashCode = gf.get("hashCode", -1);
         if (authority == null
-                && ((host != null && host.length() > 0) || port != -1)) {
+                && ((host != null && !host.isEmpty()) || port != -1)) {
             if (host == null)
                 host = "";
             authority = (port == -1) ? host : host + ":" + port;
@@ -1560,7 +1566,7 @@ public final class URL implements java.io.Serializable {
 
         // Construct authority part
         if (authority == null
-            && ((host != null && host.length() > 0) || port != -1)) {
+            && ((host != null && !host.isEmpty()) || port != -1)) {
             if (host == null)
                 host = "";
             authority = (port == -1) ? host : host + ":" + port;
@@ -1716,7 +1722,7 @@ final class UrlDeserializedState {
 
         // pre-compute length of StringBuffer
         int len = protocol.length() + 1;
-        if (authority != null && authority.length() > 0)
+        if (authority != null && !authority.isEmpty())
             len += 2 + authority.length();
         if (file != null) {
             len += file.length();
@@ -1726,7 +1732,7 @@ final class UrlDeserializedState {
         StringBuilder result = new StringBuilder(len);
         result.append(protocol);
         result.append(":");
-        if (authority != null && authority.length() > 0) {
+        if (authority != null && !authority.isEmpty()) {
             result.append("//");
             result.append(authority);
         }

src/java.base/share/classes/java/net/URLClassLoader.java

@@ -743,7 +743,7 @@ public class URLClassLoader extends SecureClassLoader implements Closeable {
                 locUrl = ((JarURLConnection)urlConnection).getJarFileURL();
             }
             String host = locUrl.getHost();
-            if (host != null && (host.length() > 0))
+            if (host != null && !host.isEmpty())
                 p = new SocketPermission(host,
                                          SecurityConstants.SOCKET_CONNECT_ACCEPT_ACTION);
         }

src/java.base/share/classes/java/net/URLConnection.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1995, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1995, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -681,7 +681,7 @@ public abstract class URLConnection {
     /**
      * Returns the value for the {@code n}<sup>th</sup> header field.
      * It returns {@code null} if there are fewer than
-     * {@code n+1}fields.
+     * {@code n+1} fields.
      * <p>
      * This method can be used in conjunction with the
      * {@link #getHeaderFieldKey(int) getHeaderFieldKey} method to iterate through all

src/java.base/share/classes/java/net/URLDecoder.java

@@ -133,7 +133,7 @@ public class URLDecoder {
      * @since 1.4
      */
     public static String decode(String s, String enc) throws UnsupportedEncodingException {
-        if (enc.length() == 0) {
+        if (enc.isEmpty()) {
             throw new UnsupportedEncodingException ("URLDecoder: empty string enc parameter");
         }
 

src/java.base/share/classes/java/net/URLPermission.java

@@ -409,7 +409,7 @@ public final class URLPermission extends Permission {
             char c = methods.charAt(i);
             if (c == ',') {
                 String s = b.toString();
-                if (s.length() > 0)
+                if (!s.isEmpty())
                     l.add(s);
                 b = new StringBuilder();
             } else if (c == ' ' || c == '\t') {
@@ -423,7 +423,7 @@ public final class URLPermission extends Permission {
             }
         }
         String s = b.toString();
-        if (s.length() > 0)
+        if (!s.isEmpty())
             l.add(s);
         return l;
     }
@@ -448,7 +448,7 @@ public final class URLPermission extends Permission {
                 b.append(c);
             } else if (c == ',') {
                 String s = b.toString();
-                if (s.length() > 0)
+                if (!s.isEmpty())
                     l.add(s);
                 b = new StringBuilder();
                 capitalizeNext = true;
@@ -458,7 +458,7 @@ public final class URLPermission extends Permission {
             }
         }
         String s = b.toString();
-        if (s.length() > 0)
+        if (!s.isEmpty())
             l.add(s);
         return l;
     }

src/java.base/share/classes/java/net/URLStreamHandler.java

@@ -235,7 +235,7 @@ public abstract class URLStreamHandler {
             start = i;
             // If the authority is defined then the path is defined by the
             // spec only; See RFC 2396 Section 5.2.4.
-            if (authority != null && authority.length() > 0)
+            if (authority != null && !authority.isEmpty())
                 path = "";
         }
 
@@ -247,7 +247,7 @@ public abstract class URLStreamHandler {
         if (start < limit) {
             if (spec.charAt(start) == '/') {
                 path = spec.substring(start, limit);
-            } else if (path != null && path.length() > 0) {
+            } else if (path != null && !path.isEmpty()) {
                 isRelPath = true;
                 int ind = path.lastIndexOf('/');
                 String separator = "";
@@ -483,11 +483,11 @@ public abstract class URLStreamHandler {
         String s;
         return u.getProtocol()
             + ':'
-            + (((s = u.getAuthority()) != null && s.length() > 0)
+            + ((s = u.getAuthority()) != null && !s.isEmpty()
                ? "//" + s : "")
-            + (((s = u.getPath()) != null) ? s : "")
-            + (((s = u.getQuery()) != null) ? '?' + s : "")
-            + (((s = u.getRef()) != null) ? '#' + s : "");
+            + ((s = u.getPath()) != null ? s : "")
+            + ((s = u.getQuery()) != null ? '?' + s : "")
+            + ((s = u.getRef()) != null ? '#' + s : "");
     }
 
     /**
@@ -544,7 +544,7 @@ public abstract class URLStreamHandler {
          */
         String authority = null;
         String userInfo = null;
-        if (host != null && host.length() != 0) {
+        if (host != null && !host.isEmpty()) {
             authority = (port == -1) ? host : host + ":" + port;
             int at = host.lastIndexOf('@');
             if (at != -1) {

src/java.base/share/classes/java/nio/file/LinkPermission.java

@@ -104,7 +104,7 @@ public final class LinkPermission extends BasicPermission {
     public LinkPermission(String name, String actions) {
         super(name);
         checkName(name);
-        if (actions != null && actions.length() > 0) {
+        if (actions != null && !actions.isEmpty()) {
             throw new IllegalArgumentException("actions: " + actions);
         }
     }

src/java.base/share/classes/java/security/AccessController.java

@@ -709,6 +709,13 @@ public final class AccessController {
         return context;
     }
 
+    /**
+     * The value needs to be physically located in the frame, so that it
+     * can be found by a stack walk.
+     */
+    @Hidden
+    private static native void ensureMaterializedForStackWalk(Object o);
+
     /**
      * Sanity check that the caller context is indeed privileged.
      *
@@ -734,6 +741,11 @@ public final class AccessController {
                           AccessControlContext context,
                           Class<?> caller)
     {
+        // Ensure context has a physical value in the frame
+        if (context != null) {
+            ensureMaterializedForStackWalk(context);
+        }
+
         assert isPrivileged(); // sanity check invariant
         T result = action.run();
         assert isPrivileged(); // sanity check invariant
@@ -742,7 +754,6 @@ public final class AccessController {
         // retrieved by getStackAccessControlContext().
         Reference.reachabilityFence(context);
         Reference.reachabilityFence(caller);
-        Reference.reachabilityFence(action);
         return result;
     }
 
@@ -761,6 +772,11 @@ public final class AccessController {
                           Class<?> caller)
         throws Exception
     {
+        // Ensure context has a physical value in the frame
+        if (context != null) {
+            ensureMaterializedForStackWalk(context);
+        }
+
         assert isPrivileged(); // sanity check invariant
         T result = action.run();
         assert isPrivileged(); // sanity check invariant
@@ -769,7 +785,6 @@ public final class AccessController {
         // retrieved by getStackAccessControlContext().
         Reference.reachabilityFence(context);
         Reference.reachabilityFence(caller);
-        Reference.reachabilityFence(action);
         return result;
     }
 

src/java.base/share/classes/java/security/AlgorithmParameterGenerator.java

@@ -228,7 +228,7 @@ public class AlgorithmParameterGenerator {
         throws NoSuchAlgorithmException, NoSuchProviderException
     {
         Objects.requireNonNull(algorithm, "null algorithm name");
-        if (provider == null || provider.length() == 0)
+        if (provider == null || provider.isEmpty())
             throw new IllegalArgumentException("missing provider");
         Object[] objs = Security.getImpl(algorithm,
                                          "AlgorithmParameterGenerator",

src/java.base/share/classes/java/security/AlgorithmParameters.java

@@ -209,7 +209,7 @@ public class AlgorithmParameters {
         throws NoSuchAlgorithmException, NoSuchProviderException
     {
         Objects.requireNonNull(algorithm, "null algorithm name");
-        if (provider == null || provider.length() == 0)
+        if (provider == null || provider.isEmpty())
             throw new IllegalArgumentException("missing provider");
         Object[] objs = Security.getImpl(algorithm, "AlgorithmParameters",
                                          provider);

src/java.base/share/classes/java/security/KeyStore.java

@@ -314,14 +314,7 @@ public class KeyStore {
         /**
          * Gets the name of the protection algorithm.
          * If none was set then the keystore provider will use its default
-         * protection algorithm. The name of the default protection algorithm
-         * for a given keystore type is set using the
-         * {@code 'keystore.<type>.keyProtectionAlgorithm'} security property.
-         * For example, the
-         * {@code keystore.PKCS12.keyProtectionAlgorithm} property stores the
-         * name of the default key protection algorithm used for PKCS12
-         * keystores. If the security property is not set, an
-         * implementation-specific algorithm will be used.
+         * protection algorithm.
          *
          * @return the algorithm name, or {@code null} if none was set
          *
@@ -920,7 +913,7 @@ public class KeyStore {
         throws KeyStoreException, NoSuchProviderException
     {
         Objects.requireNonNull(type, "null type name");
-        if (provider == null || provider.length() == 0)
+        if (provider == null || provider.isEmpty())
             throw new IllegalArgumentException("missing provider");
         try {
             Object[] objs = Security.getImpl(type, "KeyStore", provider);
@@ -1813,8 +1806,8 @@ public class KeyStore {
             }
         }
 
-        throw new KeyStoreException("This keystore does not support probing "
-                + "and must be loaded with a specified type");
+        throw new KeyStoreException("Unrecognized keystore format. "
+                + "Please load it with a specified type");
     }
 
     /**

src/java.base/share/classes/java/security/MessageDigest.java

@@ -237,7 +237,7 @@ public abstract class MessageDigest extends MessageDigestSpi {
         throws NoSuchAlgorithmException, NoSuchProviderException
     {
         Objects.requireNonNull(algorithm, "null algorithm name");
-        if (provider == null || provider.length() == 0)
+        if (provider == null || provider.isEmpty())
             throw new IllegalArgumentException("missing provider");
         Object[] objs = Security.getImpl(algorithm, "MessageDigest", provider);
         if (objs[0] instanceof MessageDigest) {

src/java.base/share/classes/java/security/Permission.java

@@ -222,7 +222,7 @@ public abstract class Permission implements Guard, java.io.Serializable {
      */
     public String toString() {
         String actions = getActions();
-        if ((actions == null) || (actions.length() == 0)) { // OPTIONAL
+        if (actions == null || actions.isEmpty()) { // OPTIONAL
             return "(\"" + getClass().getName() + "\" \"" + name + "\")";
         } else {
             return "(\"" + getClass().getName() + "\" \"" + name +

src/java.base/share/classes/java/security/Policy.java

@@ -456,7 +456,7 @@ public abstract class Policy {
                 throws NoSuchProviderException, NoSuchAlgorithmException {
 
         Objects.requireNonNull(type, "null type name");
-        if (provider == null || provider.length() == 0) {
+        if (provider == null || provider.isEmpty()) {
             throw new IllegalArgumentException("missing provider");
         }
 

src/java.base/share/classes/java/security/Provider.java

@@ -33,6 +33,7 @@ import java.lang.reflect.*;
 import java.util.function.BiConsumer;
 import java.util.function.BiFunction;
 import java.util.function.Function;
+import java.util.concurrent.ConcurrentHashMap;
 
 /**
  * This class represents a "provider" for the
@@ -225,6 +226,7 @@ public abstract class Provider extends Properties {
         this.version = version;
         this.versionStr = Double.toString(version);
         this.info = info;
+        this.serviceMap = new ConcurrentHashMap<>();
         putId();
         initialized = true;
     }
@@ -262,6 +264,7 @@ public abstract class Provider extends Properties {
         this.versionStr = versionStr;
         this.version = parseVersionStr(versionStr);
         this.info = info;
+        this.serviceMap = new ConcurrentHashMap<>();
         putId();
         initialized = true;
     }
@@ -852,10 +855,7 @@ public abstract class Provider extends Properties {
     // legacy properties changed since last call to any services method?
     private transient boolean legacyChanged;
     // serviceMap changed since last call to getServices()
-    private transient boolean servicesChanged;
-
-    // Map<String,String>
-    private transient Map<String,String> legacyStrings;
+    private volatile transient boolean servicesChanged;
 
     // Map<ServiceKey,Service>
     // used for services added via putService(), initialized on demand
@@ -905,22 +905,18 @@ public abstract class Provider extends Properties {
             // otherwise, set version based on versionStr
             this.version = parseVersionStr(this.versionStr);
         }
+        this.serviceMap = new ConcurrentHashMap<>();
         implClear();
         initialized = true;
         putAll(copy);
     }
 
-    private boolean checkLegacy(Object key) {
+    private static boolean isProviderInfo(Object key) {
         String keyString = (String)key;
         if (keyString.startsWith("Provider.")) {
-            return false;
+            return true;
         }
-
-        legacyChanged = true;
-        if (legacyStrings == null) {
-            legacyStrings = new LinkedHashMap<>();
-        }
-        return true;
+        return false;
     }
 
     /**
@@ -936,20 +932,20 @@ public abstract class Provider extends Properties {
 
     private Object implRemove(Object key) {
         if (key instanceof String) {
-            if (!checkLegacy(key)) {
+            if (isProviderInfo(key)) {
                 return null;
             }
-            legacyStrings.remove((String)key);
+            legacyChanged = true;
         }
         return super.remove(key);
     }
 
     private boolean implRemove(Object key, Object value) {
         if (key instanceof String && value instanceof String) {
-            if (!checkLegacy(key)) {
+            if (isProviderInfo(key)) {
                 return false;
             }
-            legacyStrings.remove((String)key, value);
+            legacyChanged = true;
         }
         return super.remove(key, value);
     }
@@ -957,21 +953,20 @@ public abstract class Provider extends Properties {
     private boolean implReplace(Object key, Object oldValue, Object newValue) {
         if ((key instanceof String) && (oldValue instanceof String) &&
                 (newValue instanceof String)) {
-            if (!checkLegacy(key)) {
+            if (isProviderInfo(key)) {
                 return false;
             }
-            legacyStrings.replace((String)key, (String)oldValue,
-                    (String)newValue);
+            legacyChanged = true;
         }
         return super.replace(key, oldValue, newValue);
     }
 
     private Object implReplace(Object key, Object value) {
         if ((key instanceof String) && (value instanceof String)) {
-            if (!checkLegacy(key)) {
+            if (isProviderInfo(key)) {
                 return null;
             }
-            legacyStrings.replace((String)key, (String)value);
+            legacyChanged = true;
         }
         return super.replace(key, value);
     }
@@ -980,12 +975,6 @@ public abstract class Provider extends Properties {
     private void implReplaceAll(BiFunction<? super Object, ? super Object,
             ? extends Object> function) {
         legacyChanged = true;
-        if (legacyStrings == null) {
-            legacyStrings = new LinkedHashMap<>();
-        } else {
-            legacyStrings.replaceAll((BiFunction<? super String, ? super String,
-                    ? extends String>) function);
-        }
         super.replaceAll(function);
     }
 
@@ -993,11 +982,10 @@ public abstract class Provider extends Properties {
     private Object implMerge(Object key, Object value, BiFunction<? super Object,
             ? super Object, ? extends Object> remappingFunction) {
         if ((key instanceof String) && (value instanceof String)) {
-            if (!checkLegacy(key)) {
+            if (isProviderInfo(key)) {
                 return null;
             }
-            legacyStrings.merge((String)key, (String)value,
-                    (BiFunction<? super String, ? super String, ? extends String>) remappingFunction);
+            legacyChanged = true;
         }
         return super.merge(key, value, remappingFunction);
     }
@@ -1006,11 +994,10 @@ public abstract class Provider extends Properties {
     private Object implCompute(Object key, BiFunction<? super Object,
             ? super Object, ? extends Object> remappingFunction) {
         if (key instanceof String) {
-            if (!checkLegacy(key)) {
+            if (isProviderInfo(key)) {
                 return null;
             }
-            legacyStrings.compute((String) key,
-                    (BiFunction<? super String,? super String, ? extends String>) remappingFunction);
+            legacyChanged = true;
         }
         return super.compute(key, remappingFunction);
     }
@@ -1019,11 +1006,10 @@ public abstract class Provider extends Properties {
     private Object implComputeIfAbsent(Object key, Function<? super Object,
             ? extends Object> mappingFunction) {
         if (key instanceof String) {
-            if (!checkLegacy(key)) {
+            if (isProviderInfo(key)) {
                 return null;
             }
-            legacyStrings.computeIfAbsent((String) key,
-                    (Function<? super String, ? extends String>) mappingFunction);
+            legacyChanged = true;
         }
         return super.computeIfAbsent(key, mappingFunction);
     }
@@ -1032,45 +1018,39 @@ public abstract class Provider extends Properties {
     private Object implComputeIfPresent(Object key, BiFunction<? super Object,
             ? super Object, ? extends Object> remappingFunction) {
         if (key instanceof String) {
-            if (!checkLegacy(key)) {
+            if (isProviderInfo(key)) {
                 return null;
             }
-            legacyStrings.computeIfPresent((String) key,
-                    (BiFunction<? super String, ? super String, ? extends String>) remappingFunction);
+            legacyChanged = true;
         }
         return super.computeIfPresent(key, remappingFunction);
     }
 
     private Object implPut(Object key, Object value) {
         if ((key instanceof String) && (value instanceof String)) {
-            if (!checkLegacy(key)) {
+            if (isProviderInfo(key)) {
                 return null;
             }
-            legacyStrings.put((String)key, (String)value);
+            legacyChanged = true;
         }
         return super.put(key, value);
     }
 
     private Object implPutIfAbsent(Object key, Object value) {
         if ((key instanceof String) && (value instanceof String)) {
-            if (!checkLegacy(key)) {
+            if (isProviderInfo(key)) {
                 return null;
             }
-            legacyStrings.putIfAbsent((String)key, (String)value);
+            legacyChanged = true;
         }
         return super.putIfAbsent(key, value);
     }
 
     private void implClear() {
-        if (legacyStrings != null) {
-            legacyStrings.clear();
-        }
         if (legacyMap != null) {
             legacyMap.clear();
         }
-        if (serviceMap != null) {
-            serviceMap.clear();
-        }
+        serviceMap.clear();
         legacyChanged = false;
         servicesChanged = false;
         serviceSet = null;
@@ -1090,13 +1070,13 @@ public abstract class Provider extends Properties {
             this.algorithm = intern ? algorithm.intern() : algorithm;
         }
         public int hashCode() {
-            return type.hashCode() + algorithm.hashCode();
+            return Objects.hash(type, algorithm);
         }
         public boolean equals(Object obj) {
             if (this == obj) {
                 return true;
             }
-            if (obj instanceof ServiceKey == false) {
+            if (!(obj instanceof ServiceKey)) {
                 return false;
             }
             ServiceKey other = (ServiceKey)obj;
@@ -1113,16 +1093,16 @@ public abstract class Provider extends Properties {
      * service objects.
      */
     private void ensureLegacyParsed() {
-        if ((legacyChanged == false) || (legacyStrings == null)) {
+        if (legacyChanged == false) {
             return;
         }
         serviceSet = null;
         if (legacyMap == null) {
-            legacyMap = new LinkedHashMap<>();
+            legacyMap = new ConcurrentHashMap<>();
         } else {
             legacyMap.clear();
         }
-        for (Map.Entry<String,String> entry : legacyStrings.entrySet()) {
+        for (Map.Entry<?,?> entry : super.entrySet()) {
             parseLegacyPut(entry.getKey(), entry.getValue());
         }
         removeInvalidServices(legacyMap);
@@ -1161,7 +1141,15 @@ public abstract class Provider extends Properties {
     private static final String ALIAS_PREFIX_LOWER = "alg.alias.";
     private static final int ALIAS_LENGTH = ALIAS_PREFIX.length();
 
-    private void parseLegacyPut(String name, String value) {
+    private void parseLegacyPut(Object k, Object v) {
+        if (!(k instanceof String) || !(v instanceof String)) {
+            return;
+        }
+        String name = (String) k;
+        String value = (String) v;
+        if (isProviderInfo(name)) {
+            return;
+        }
         if (name.toLowerCase(ENGLISH).startsWith(ALIAS_PREFIX_LOWER)) {
             // e.g. put("Alg.Alias.MessageDigest.SHA", "SHA-1");
             // aliasKey ~ MessageDigest.SHA
@@ -1248,22 +1236,28 @@ public abstract class Provider extends Properties {
      *
      * @since 1.5
      */
-    public synchronized Service getService(String type, String algorithm) {
+    public Service getService(String type, String algorithm) {
         checkInitialized();
-        // avoid allocating a new key object if possible
+
+        // avoid allocating a new ServiceKey object if possible
         ServiceKey key = previousKey;
         if (key.matches(type, algorithm) == false) {
             key = new ServiceKey(type, algorithm, false);
             previousKey = key;
         }
-        if (serviceMap != null) {
-            Service service = serviceMap.get(key);
-            if (service != null) {
-                return service;
+        if (!serviceMap.isEmpty()) {
+            Service s = serviceMap.get(key);
+            if (s != null) {
+                return s;
             }
         }
-        ensureLegacyParsed();
-        return (legacyMap != null) ? legacyMap.get(key) : null;
+        synchronized (this) {
+            ensureLegacyParsed();
+        }
+        if (legacyMap != null && !legacyMap.isEmpty()) {
+            return legacyMap.get(key);
+        }
+        return null;
     }
 
     // ServiceKey from previous getService() call
@@ -1292,10 +1286,10 @@ public abstract class Provider extends Properties {
         if (serviceSet == null) {
             ensureLegacyParsed();
             Set<Service> set = new LinkedHashSet<>();
-            if (serviceMap != null) {
+            if (!serviceMap.isEmpty()) {
                 set.addAll(serviceMap.values());
             }
-            if (legacyMap != null) {
+            if (legacyMap != null && !legacyMap.isEmpty()) {
                 set.addAll(legacyMap.values());
             }
             serviceSet = Collections.unmodifiableSet(set);
@@ -1333,7 +1327,7 @@ public abstract class Provider extends Properties {
      *
      * @since 1.5
      */
-    protected synchronized void putService(Service s) {
+    protected void putService(Service s) {
         check("putProviderProperty." + name);
         if (debug != null) {
             debug.println(name + ".putService(): " + s);
@@ -1345,20 +1339,18 @@ public abstract class Provider extends Properties {
             throw new IllegalArgumentException
                     ("service.getProvider() must match this Provider object");
         }
-        if (serviceMap == null) {
-            serviceMap = new LinkedHashMap<>();
-        }
-        servicesChanged = true;
         String type = s.getType();
         String algorithm = s.getAlgorithm();
         ServiceKey key = new ServiceKey(type, algorithm, true);
-        // remove existing service
         implRemoveService(serviceMap.get(key));
         serviceMap.put(key, s);
         for (String alias : s.getAliases()) {
             serviceMap.put(new ServiceKey(type, alias, true), s);
         }
-        putPropertyStrings(s);
+        servicesChanged = true;
+        synchronized (this) {
+            putPropertyStrings(s);
+        }
     }
 
     /**
@@ -1425,7 +1417,7 @@ public abstract class Provider extends Properties {
      *
      * @since 1.5
      */
-    protected synchronized void removeService(Service s) {
+    protected void removeService(Service s) {
         check("removeProviderProperty." + name);
         if (debug != null) {
             debug.println(name + ".removeService(): " + s);
@@ -1437,7 +1429,7 @@ public abstract class Provider extends Properties {
     }
 
     private void implRemoveService(Service s) {
-        if ((s == null) || (serviceMap == null)) {
+        if ((s == null) || serviceMap.isEmpty()) {
             return;
         }
         String type = s.getType();
@@ -1452,7 +1444,9 @@ public abstract class Provider extends Properties {
         for (String alias : s.getAliases()) {
             serviceMap.remove(new ServiceKey(type, alias, false));
         }
-        removePropertyStrings(s);
+        synchronized (this) {
+            removePropertyStrings(s);
+        }
     }
 
     // Wrapped String that behaves in a case insensitive way for equals/hashCode

src/java.base/share/classes/java/security/SecureRandom.java

@@ -942,7 +942,7 @@ public class SecureRandom extends java.util.Random {
                 }
             });
 
-        if ((property == null) || (property.length() == 0)) {
+        if (property == null || property.isEmpty()) {
             throw new NoSuchAlgorithmException(
                 "Null/empty securerandom.strongAlgorithms Security Property");
         }

src/java.base/share/classes/java/security/Security.java

@@ -649,7 +649,7 @@ public final class Security {
             }
         }
 
-        if ((candidates == null) || (candidates.isEmpty()))
+        if (candidates == null || candidates.isEmpty())
             return null;
 
         Object[] candidatesArray = candidates.toArray();
@@ -1005,11 +1005,11 @@ public final class Security {
         String algName = null;
         String attrName = null;
 
-        if (filterValue.length() == 0) {
+        if (filterValue.isEmpty()) {
             // The filterValue is an empty string. So the filterKey
             // should be in the format of <crypto_service>.<algorithm_or_type>.
             algName = filterKey.substring(algIndex + 1).trim();
-            if (algName.length() == 0) {
+            if (algName.isEmpty()) {
                 // There must be a algorithm or type name.
                 throw new InvalidParameterException("Invalid filter");
             }
@@ -1024,7 +1024,7 @@ public final class Security {
                 throw new InvalidParameterException("Invalid filter");
             } else {
                 attrName = filterKey.substring(attrIndex + 1).trim();
-                if (attrName.length() == 0) {
+                if (attrName.isEmpty()) {
                     // There is no attribute name in the filter.
                     throw new InvalidParameterException("Invalid filter");
                 }
@@ -1070,7 +1070,7 @@ public final class Security {
      **/
     public static Set<String> getAlgorithms(String serviceName) {
 
-        if ((serviceName == null) || (serviceName.length() == 0) ||
+        if ((serviceName == null) || (serviceName.isEmpty()) ||
             (serviceName.endsWith("."))) {
             return Collections.emptySet();
         }

src/java.base/share/classes/java/security/Signature.java

@@ -360,7 +360,7 @@ public abstract class Signature extends SignatureSpi {
         Objects.requireNonNull(algorithm, "null algorithm name");
         if (algorithm.equalsIgnoreCase(RSA_SIGNATURE)) {
             // exception compatibility with existing code
-            if ((provider == null) || (provider.length() == 0)) {
+            if (provider == null || provider.isEmpty()) {
                 throw new IllegalArgumentException("missing provider");
             }
             Provider p = Security.getProvider(provider);

src/java.base/share/classes/java/security/cert/TrustAnchor.java

@@ -210,7 +210,7 @@ public class TrustAnchor {
         if (caName == null)
             throw new NullPointerException("the caName parameter must be " +
                 "non-null");
-        if (caName.length() == 0)
+        if (caName.isEmpty())
             throw new IllegalArgumentException("the caName " +
                 "parameter must be a non-empty String");
         // check if caName is formatted correctly

src/java.base/share/classes/java/text/AttributedString.java

@@ -85,7 +85,7 @@ public class AttributedString {
 
             text = buffer.toString();
 
-            if (text.length() > 0) {
+            if (!text.isEmpty()) {
                 // Determine the runs, creating a new run when the attributes
                 // differ.
                 int offset = 0;
@@ -144,7 +144,7 @@ public class AttributedString {
         }
         this.text = text;
 
-        if (text.length() == 0) {
+        if (text.isEmpty()) {
             if (attributes.isEmpty())
                 return;
             throw new IllegalArgumentException("Can't add attribute to 0-length text");

src/java.base/share/classes/java/text/CollationElementIterator.java

@@ -125,7 +125,7 @@ public final class CollationElementIterator
     CollationElementIterator(String sourceText, RuleBasedCollator owner) {
         this.owner = owner;
         ordering = owner.getTables();
-        if ( sourceText.length() != 0 ) {
+        if (!sourceText.isEmpty()) {
             NormalizerBase.Mode mode =
                 CollatorUtilities.toNormalizerMode(owner.getDecomposition());
             text = new NormalizerBase(sourceText, mode);

src/java.base/share/classes/java/text/CompactNumberFormat.java

@@ -799,7 +799,7 @@ public final class CompactNumberFormat extends NumberFormat {
      */
     private void append(StringBuffer result, String string,
             FieldDelegate delegate, List<FieldPosition> positions) {
-        if (string.length() > 0) {
+        if (!string.isEmpty()) {
             int start = result.length();
             result.append(string);
             for (int counter = 0; counter < positions.size(); counter++) {
@@ -1213,7 +1213,7 @@ public final class CompactNumberFormat extends NumberFormat {
         }
 
         // If no 0s are specified in a non empty pattern, it is invalid
-        if (pattern.length() != 0 && zeros.isEmpty()) {
+        if (!pattern.isEmpty() && zeros.isEmpty()) {
             throw new IllegalArgumentException("Invalid pattern"
                     + " [" + pattern + "]: all patterns must include digit"
                     + " placement 0s");

src/java.base/share/classes/java/text/DecimalFormat.java

@@ -1113,11 +1113,9 @@ public class DecimalFormat extends NumberFormat {
 
             // Records the need for adding prefix or suffix
             fastPathData.positiveAffixesRequired
-                    = (positivePrefix.length() != 0)
-                        || (positiveSuffix.length() != 0);
+                    = !positivePrefix.isEmpty() || !positiveSuffix.isEmpty();
             fastPathData.negativeAffixesRequired
-                    = (negativePrefix.length() != 0)
-                        || (negativeSuffix.length() != 0);
+                    = !negativePrefix.isEmpty() || !negativeSuffix.isEmpty();
 
             // Creates a cached char container for result, with max possible size.
             int maxNbIntegralDigits = 10;
@@ -2062,7 +2060,7 @@ public class DecimalFormat extends NumberFormat {
                         Format.Field signAttribute) {
         int start = result.length();
 
-        if (string.length() > 0) {
+        if (!string.isEmpty()) {
             result.append(string);
             for (int counter = 0, max = positions.length; counter < max;
                  counter++) {
@@ -3042,7 +3040,7 @@ public class DecimalFormat extends NumberFormat {
                     } else {
                         string = symbols.getCurrencySymbol();
                     }
-                    if (string.length() > 0) {
+                    if (!string.isEmpty()) {
                         if (positions == null) {
                             positions = new ArrayList<>(2);
                         }
@@ -3613,7 +3611,7 @@ public class DecimalFormat extends NumberFormat {
             }
         }
 
-        if (pattern.length() == 0) {
+        if (pattern.isEmpty()) {
             posPrefixPattern = posSuffixPattern = "";
             setMinimumIntegerDigits(0);
             setMaximumIntegerDigits(MAXIMUM_INTEGER_DIGITS);

src/java.base/share/classes/java/text/DecimalFormatSymbols.java

@@ -663,7 +663,7 @@ public class DecimalFormatSymbols implements Cloneable, Serializable {
         // Check for empty country string separately because it's a valid
         // country ID for Locale (and used for the C locale), but not a valid
         // ISO 3166 country code, and exceptions are expensive.
-        if (locale.getCountry().length() > 0) {
+        if (!locale.getCountry().isEmpty()) {
             try {
                 currency = Currency.getInstance(locale);
             } catch (IllegalArgumentException e) {

src/java.base/share/classes/java/text/MergeCollation.java

@@ -92,7 +92,7 @@ final class MergeCollation {
         int i;
         for (i = 0; i < patterns.size(); ++i) {
             PatternEntry entry = patterns.get(i);
-            if (entry.extension.length() != 0) {
+            if (!entry.extension.isEmpty()) {
                 if (extList == null)
                     extList = new ArrayList<>();
                 extList.add(entry);
@@ -122,7 +122,7 @@ final class MergeCollation {
     private final PatternEntry findLastWithNoExtension(int i) {
         for (--i;i >= 0; --i) {
             PatternEntry entry = patterns.get(i);
-            if (entry.extension.length() == 0) {
+            if (entry.extension.isEmpty()) {
                 return entry;
             }
         }

src/java.base/share/classes/java/text/MessageFormat.java

@@ -1330,7 +1330,7 @@ public class MessageFormat extends Format {
                         }
                         arg = null;
                     }
-                    if (arg != null && arg.length() > 0) {
+                    if (arg != null && !arg.isEmpty()) {
                         result.append(arg);
                         characterIterators.add(
                                  createAttributedCharacterIterator(
@@ -1476,7 +1476,7 @@ public class MessageFormat extends Format {
 
         // now get the format
         Format newFormat = null;
-        if (segments[SEG_TYPE].length() != 0) {
+        if (!segments[SEG_TYPE].isEmpty()) {
             int type = findKeyword(segments[SEG_TYPE], TYPE_KEYWORDS);
             switch (type) {
             case TYPE_NULL:

src/java.base/share/classes/java/text/PatternEntry.java

@@ -141,7 +141,7 @@ class PatternEntry {
         if (showWhiteSpace)
             toAddTo.append(' ');
         appendQuoted(chars,toAddTo);
-        if (showExtension && extension.length() != 0) {
+        if (showExtension && !extension.isEmpty()) {
             toAddTo.append('/');
             appendQuoted(extension,toAddTo);
         }

src/java.base/share/classes/java/text/RBTableBuilder.java

@@ -75,13 +75,10 @@ final class RBTableBuilder {
      * @exception ParseException If the rules format is incorrect.
      */
 
-    public void build(String pattern, int decmp) throws ParseException
-    {
-        boolean isSource = true;
-        int i = 0;
+    public void build(String pattern, int decmp) throws ParseException {
         String expChars;
         String groupChars;
-        if (pattern.length() == 0)
+        if (pattern.isEmpty())
             throw new ParseException("Build rules empty.", 0);
 
         // This array maps Unicode characters to their collation ordering
@@ -119,8 +116,7 @@ final class RBTableBuilder {
         int order = 0;
 
         // Now walk though each entry and add it to my own tables
-        for (i = 0; i < mPattern.getCount(); ++i)
-        {
+        for (int i = 0; i < mPattern.getCount(); ++i) {
             PatternEntry entry = mPattern.getItemAt(i);
             if (entry != null) {
                 groupChars = entry.getChars();
@@ -140,7 +136,7 @@ final class RBTableBuilder {
                 order = increment(entry.getStrength(), order);
                 expChars = entry.getExtension();
 
-                if (expChars.length() != 0) {
+                if (!expChars.isEmpty()) {
                     addExpandOrder(groupChars, expChars, order);
                 } else if (groupChars.length() > 1) {
                     char ch = groupChars.charAt(0);

src/java.base/share/classes/java/time/ZoneId.java

@@ -372,7 +372,7 @@ public abstract class ZoneId implements Serializable {
     public static ZoneId ofOffset(String prefix, ZoneOffset offset) {
         Objects.requireNonNull(prefix, "prefix");
         Objects.requireNonNull(offset, "offset");
-        if (prefix.length() == 0) {
+        if (prefix.isEmpty()) {
             return offset;
         }
 

src/java.base/share/classes/java/time/format/DateTimeFormatterBuilder.java

@@ -1439,7 +1439,7 @@ public final class DateTimeFormatterBuilder {
      */
     public DateTimeFormatterBuilder appendLiteral(String literal) {
         Objects.requireNonNull(literal, "literal");
-        if (literal.length() > 0) {
+        if (!literal.isEmpty()) {
             if (literal.length() == 1) {
                 appendInternal(new CharLiteralPrinterParser(literal.charAt(0)));
             } else {
@@ -1832,7 +1832,7 @@ public final class DateTimeFormatterBuilder {
                     throw new IllegalArgumentException("Pattern ends with an incomplete string literal: " + pattern);
                 }
                 String str = pattern.substring(start + 1, pos);
-                if (str.length() == 0) {
+                if (str.isEmpty()) {
                     appendLiteral('\'');
                 } else {
                     appendLiteral(str.replace("''", "'"));
@@ -4332,7 +4332,7 @@ public final class DateTimeFormatterBuilder {
             this.key = k;
             this.value = v;
             this.child = child;
-            if (k.length() == 0){
+            if (k.isEmpty()) {
                 c0 = 0xffff;
             } else {
                 c0 = key.charAt(0);

src/java.base/share/classes/java/time/zone/ZoneRulesProvider.java

@@ -99,7 +99,7 @@ import java.util.Collections;
  * <p>
  * The Java virtual machine has a default provider that provides zone rules
  * for the time-zones defined by IANA Time Zone Database (TZDB). If the system
- * property {@code java.time.zone.DefaultZoneRulesProvider} is defined then
+ * property {@systemProperty java.time.zone.DefaultZoneRulesProvider} is defined then
  * it is taken to be the fully-qualified name of a concrete ZoneRulesProvider
  * class to be loaded as the default provider, using the system class loader.
  * If this system property is not defined, a system-default provider will be

src/java.base/share/classes/java/util/Calendar.java

@@ -2232,7 +2232,7 @@ public abstract class Calendar implements Serializable, Cloneable, Comparable<Ca
         if (strings != null) {
             Map<String,Integer> names = new HashMap<>();
             for (int i = 0; i < strings.length; i++) {
-                if (strings[i].length() == 0) {
+                if (strings[i].isEmpty()) {
                     continue;
                 }
                 names.put(strings[i], i);

src/java.base/share/classes/java/util/Collections.java

@@ -459,7 +459,7 @@ public class Collections {
             for (int i=size; i>1; i--)
                 swap(list, i-1, rnd.nextInt(i));
         } else {
-            Object arr[] = list.toArray();
+            Object[] arr = list.toArray();
 
             // Shuffle array
             for (int i=size; i>1; i--)
@@ -5101,6 +5101,53 @@ public class Collections {
             return new CopiesList<>(toIndex - fromIndex, element);
         }
 
+        @Override
+        public int hashCode() {
+            if (n == 0) return 1;
+            // hashCode of n repeating elements is 31^n + elementHash * Sum(31^k, k = 0..n-1)
+            // this implementation completes in O(log(n)) steps taking advantage of
+            // 31^(2*n) = (31^n)^2 and Sum(31^k, k = 0..(2*n-1)) = Sum(31^k, k = 0..n-1) * (31^n + 1)
+            int pow = 31;
+            int sum = 1;
+            for (int i = Integer.numberOfLeadingZeros(n) + 1; i < Integer.SIZE; i++) {
+                sum *= pow + 1;
+                pow *= pow;
+                if ((n << i) < 0) {
+                    pow *= 31;
+                    sum = sum * 31 + 1;
+                }
+            }
+            return pow + sum * (element == null ? 0 : element.hashCode());
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (o == this)
+                return true;
+            if (o instanceof CopiesList) {
+                CopiesList<?> other = (CopiesList<?>) o;
+                return n == other.n && (n == 0 || eq(element, other.element));
+            }
+            if (!(o instanceof List))
+                return false;
+
+            int remaining = n;
+            E e = element;
+            Iterator<?> itr = ((List<?>) o).iterator();
+            if (e == null) {
+                while (itr.hasNext() && remaining-- > 0) {
+                    if (itr.next() != null)
+                        return false;
+                }
+            } else {
+                while (itr.hasNext() && remaining-- > 0) {
+                    if (!e.equals(itr.next()))
+                        return false;
+                }
+            }
+            return remaining == 0 && !itr.hasNext();
+        }
+
         // Override default methods in Collection
         @Override
         public Stream<E> stream() {

src/java.base/share/classes/java/util/Currency.java

@@ -60,7 +60,7 @@ import sun.util.logging.PlatformLogger;
  * the <code>getInstance</code> methods.
  * <p>
  * Users can supersede the Java runtime currency data by means of the system
- * property {@code java.util.currency.data}. If this system property is
+ * property {@systemProperty java.util.currency.data}. If this system property is
  * defined then its value is the location of a properties file, the contents of
  * which are key/value pairs of the ISO 3166 country codes and the ISO 4217
  * currency data respectively.  The value part consists of three ISO 4217 values

src/java.base/share/classes/java/util/Locale.java

@@ -1396,11 +1396,11 @@ public final class Locale implements Cloneable, Serializable {
      */
     @Override
     public final String toString() {
-        boolean l = (baseLocale.getLanguage().length() != 0);
-        boolean s = (baseLocale.getScript().length() != 0);
-        boolean r = (baseLocale.getRegion().length() != 0);
-        boolean v = (baseLocale.getVariant().length() != 0);
-        boolean e = (localeExtensions != null && localeExtensions.getID().length() != 0);
+        boolean l = !baseLocale.getLanguage().isEmpty();
+        boolean s = !baseLocale.getScript().isEmpty();
+        boolean r = !baseLocale.getRegion().isEmpty();
+        boolean v = !baseLocale.getVariant().isEmpty();
+        boolean e = localeExtensions != null && !localeExtensions.getID().isEmpty();
 
         StringBuilder result = new StringBuilder(baseLocale.getLanguage());
         if (r || (l && (v || s || e))) {
@@ -1504,18 +1504,18 @@ public final class Locale implements Cloneable, Serializable {
         StringBuilder buf = new StringBuilder();
 
         String subtag = tag.getLanguage();
-        if (subtag.length() > 0) {
+        if (!subtag.isEmpty()) {
             buf.append(LanguageTag.canonicalizeLanguage(subtag));
         }
 
         subtag = tag.getScript();
-        if (subtag.length() > 0) {
+        if (!subtag.isEmpty()) {
             buf.append(LanguageTag.SEP);
             buf.append(LanguageTag.canonicalizeScript(subtag));
         }
 
         subtag = tag.getRegion();
-        if (subtag.length() > 0) {
+        if (!subtag.isEmpty()) {
             buf.append(LanguageTag.SEP);
             buf.append(LanguageTag.canonicalizeRegion(subtag));
         }
@@ -1534,7 +1534,7 @@ public final class Locale implements Cloneable, Serializable {
         }
 
         subtag = tag.getPrivateuse();
-        if (subtag.length() > 0) {
+        if (!subtag.isEmpty()) {
             if (buf.length() > 0) {
                 buf.append(LanguageTag.SEP);
             }
@@ -1684,7 +1684,7 @@ public final class Locale implements Cloneable, Serializable {
         bldr.setLanguageTag(tag);
         BaseLocale base = bldr.getBaseLocale();
         LocaleExtensions exts = bldr.getLocaleExtensions();
-        if (exts == null && base.getVariant().length() > 0) {
+        if (exts == null && !base.getVariant().isEmpty()) {
             exts = getCompatibilityExtensions(base.getLanguage(), base.getScript(),
                                               base.getRegion(), base.getVariant());
         }
@@ -1917,7 +1917,7 @@ public final class Locale implements Cloneable, Serializable {
      * @exception NullPointerException if <code>inLocale</code> is <code>null</code>
      */
     public String getDisplayVariant(Locale inLocale) {
-        if (baseLocale.getVariant().length() == 0)
+        if (baseLocale.getVariant().isEmpty())
             return "";
 
         LocaleResources lr = LocaleProviderAdapter
@@ -1998,14 +1998,14 @@ public final class Locale implements Cloneable, Serializable {
         // The display name consists of a main name, followed by qualifiers.
         // Typically, the format is "MainName (Qualifier, Qualifier)" but this
         // depends on what pattern is stored in the display locale.
-        String   mainName       = null;
-        String[] qualifierNames = null;
+        String   mainName;
+        String[] qualifierNames;
 
         // The main name is the language, or if there is no language, the script,
         // then if no script, the country. If there is no language/script/country
         // (an anomalous situation) then the display name is simply the variant's
         // display name.
-        if (languageName.length() == 0 && scriptName.length() == 0 && countryName.length() == 0) {
+        if (languageName.isEmpty() && scriptName.isEmpty() && countryName.isEmpty()) {
             if (variantNames.length == 0) {
                 return "";
             } else {
@@ -2013,13 +2013,13 @@ public final class Locale implements Cloneable, Serializable {
             }
         }
         ArrayList<String> names = new ArrayList<>(4);
-        if (languageName.length() != 0) {
+        if (!languageName.isEmpty()) {
             names.add(languageName);
         }
-        if (scriptName.length() != 0) {
+        if (!scriptName.isEmpty()) {
             names.add(scriptName);
         }
-        if (countryName.length() != 0) {
+        if (!countryName.isEmpty()) {
             names.add(countryName);
         }
         if (variantNames.length != 0) {
@@ -2309,7 +2309,7 @@ public final class Locale implements Cloneable, Serializable {
         String variant = (String)fields.get("variant", "");
         String extStr = (String)fields.get("extensions", "");
         baseLocale = BaseLocale.getInstance(convertOldISOCodes(language), script, country, variant);
-        if (extStr.length() > 0) {
+        if (!extStr.isEmpty()) {
             try {
                 InternalLocaleBuilder bldr = new InternalLocaleBuilder();
                 bldr.setExtensions(extStr);
@@ -2367,13 +2367,13 @@ public final class Locale implements Cloneable, Serializable {
         LocaleExtensions extensions = null;
         // Special cases for backward compatibility support
         if (LocaleUtils.caseIgnoreMatch(language, "ja")
-                && script.length() == 0
+                && script.isEmpty()
                 && LocaleUtils.caseIgnoreMatch(country, "jp")
                 && "JP".equals(variant)) {
             // ja_JP_JP -> u-ca-japanese (calendar = japanese)
             extensions = LocaleExtensions.CALENDAR_JAPANESE;
         } else if (LocaleUtils.caseIgnoreMatch(language, "th")
-                && script.length() == 0
+                && script.isEmpty()
                 && LocaleUtils.caseIgnoreMatch(country, "th")
                 && "TH".equals(variant)) {
             // th_TH_TH -> u-nu-thai (numbersystem = thai)
@@ -2806,7 +2806,7 @@ public final class Locale implements Cloneable, Serializable {
         public Locale build() {
             BaseLocale baseloc = localeBuilder.getBaseLocale();
             LocaleExtensions extensions = localeBuilder.getLocaleExtensions();
-            if (extensions == null && baseloc.getVariant().length() > 0) {
+            if (extensions == null && !baseloc.getVariant().isEmpty()) {
                 extensions = getCompatibilityExtensions(baseloc.getLanguage(), baseloc.getScript(),
                         baseloc.getRegion(), baseloc.getVariant());
             }

src/java.base/share/classes/java/util/PropertyResourceBundle.java

@@ -115,7 +115,7 @@ import sun.util.ResourceBundleEnumeration;
  * input stream, then the {@code PropertyResourceBundle} instance resets to the state
  * before the exception, re-reads the input stream in {@code ISO-8859-1}, and
  * continues reading. If the system property
- * {@code java.util.PropertyResourceBundle.encoding} is set to either
+ * {@systemProperty java.util.PropertyResourceBundle.encoding} is set to either
  * "ISO-8859-1" or "UTF-8", the input stream is solely read in that encoding,
  * and throws the exception if it encounters an invalid sequence.
  * If "ISO-8859-1" is specified, characters that cannot be represented in

src/java.base/share/classes/java/util/ResourceBundle.java

@@ -771,8 +771,8 @@ public abstract class ResourceBundle {
         @Override
         public String toString() {
             String l = locale.toString();
-            if (l.length() == 0) {
-                if (locale.getVariant().length() != 0) {
+            if (l.isEmpty()) {
+                if (!locale.getVariant().isEmpty()) {
                     l = "__" + locale.getVariant();
                 } else {
                     l = "\"\"";
@@ -2903,7 +2903,7 @@ public abstract class ResourceBundle {
                     List<Locale> bokmalList = new LinkedList<>();
                     for (Locale l : tmpList) {
                         bokmalList.add(l);
-                        if (l.getLanguage().length() == 0) {
+                        if (l.getLanguage().isEmpty()) {
                             break;
                         }
                         bokmalList.add(Locale.getInstance("no", l.getScript(), l.getCountry(),
@@ -2921,7 +2921,7 @@ public abstract class ResourceBundle {
                 }
                 // Special handling for Chinese
                 else if (language.equals("zh")) {
-                    if (script.length() == 0 && region.length() > 0) {
+                    if (script.isEmpty() && !region.isEmpty()) {
                         // Supply script for users who want to use zh_Hans/zh_Hant
                         // as bundle names (recommended for Java7+)
                         switch (region) {
@@ -2944,7 +2944,7 @@ public abstract class ResourceBundle {
             private static List<Locale> getDefaultList(String language, String script, String region, String variant) {
                 List<String> variants = null;
 
-                if (variant.length() > 0) {
+                if (!variant.isEmpty()) {
                     variants = new LinkedList<>();
                     int idx = variant.length();
                     while (idx != -1) {
@@ -2960,14 +2960,14 @@ public abstract class ResourceBundle {
                         list.add(Locale.getInstance(language, script, region, v, null));
                     }
                 }
-                if (region.length() > 0) {
+                if (!region.isEmpty()) {
                     list.add(Locale.getInstance(language, script, region, "", null));
                 }
-                if (script.length() > 0) {
+                if (!script.isEmpty()) {
                     list.add(Locale.getInstance(language, script, "", "", null));
                     // Special handling for Chinese
                     if (language.equals("zh")) {
-                        if (region.length() == 0) {
+                        if (region.isEmpty()) {
                             // Supply region(country) for users who still package Chinese
                             // bundles using old convension.
                             switch (script) {
@@ -2988,11 +2988,11 @@ public abstract class ResourceBundle {
                             list.add(Locale.getInstance(language, "", region, v, null));
                         }
                     }
-                    if (region.length() > 0) {
+                    if (!region.isEmpty()) {
                         list.add(Locale.getInstance(language, "", region, "", null));
                     }
                 }
-                if (language.length() > 0) {
+                if (!language.isEmpty()) {
                     list.add(Locale.getInstance(language, "", "", "", null));
                 }
                 // Add root locale at the end

src/java.base/share/classes/java/util/Scanner.java

@@ -1297,16 +1297,16 @@ public final class Scanner implements Iterator<String>, Closeable {
         nanString = "\\Q" + dfs.getNaN() + "\\E";
         infinityString = "\\Q" + dfs.getInfinity() + "\\E";
         positivePrefix = df.getPositivePrefix();
-        if (positivePrefix.length() > 0)
+        if (!positivePrefix.isEmpty())
             positivePrefix = "\\Q" + positivePrefix + "\\E";
         negativePrefix = df.getNegativePrefix();
-        if (negativePrefix.length() > 0)
+        if (!negativePrefix.isEmpty())
             negativePrefix = "\\Q" + negativePrefix + "\\E";
         positiveSuffix = df.getPositiveSuffix();
-        if (positiveSuffix.length() > 0)
+        if (!positiveSuffix.isEmpty())
             positiveSuffix = "\\Q" + positiveSuffix + "\\E";
         negativeSuffix = df.getNegativeSuffix();
-        if (negativeSuffix.length() > 0)
+        if (!negativeSuffix.isEmpty())
             negativeSuffix = "\\Q" + negativeSuffix + "\\E";
 
         // Force rebuilding and recompilation of locale dependent

src/java.base/share/classes/java/util/Spliterator.java

@@ -284,7 +284,7 @@ import java.util.function.LongConsumer;
  * }}</pre>
  *
  * @implNote
- * If the boolean system property {@code org.openjdk.java.util.stream.tripwire}
+ * If the boolean system property {@systemProperty org.openjdk.java.util.stream.tripwire}
  * is set to {@code true} then diagnostic warnings are reported if boxing of
  * primitive values occur when operating on primitive subtype specializations.
  *

src/java.base/share/classes/java/util/concurrent/ForkJoinPool.java

@@ -445,7 +445,8 @@ public class ForkJoinPool extends AbstractExecutorService {
      * if to its current value).  This would be extremely costly. So
      * we relax it in several ways: (1) Producers only signal when
      * their queue is possibly empty at some point during a push
-     * operation. (2) Other workers propagate this signal
+     * operation (which requires conservatively checking size zero or
+     * one to cover races). (2) Other workers propagate this signal
      * when they find tasks in a queue with size greater than one. (3)
      * Workers only enqueue after scanning (see below) and not finding
      * any tasks.  (4) Rather than CASing ctl to its current value in
@@ -761,8 +762,10 @@ public class ForkJoinPool extends AbstractExecutorService {
 
     /**
      * The maximum number of top-level polls per worker before
-     * checking other queues, expressed as a bit shift.  See above for
-     * rationale.
+     * checking other queues, expressed as a bit shift to, in effect,
+     * multiply by pool size, and then use as random value mask, so
+     * average bound is about poolSize*(1<<TOP_BOUND_SHIFT).  See
+     * above for rationale.
      */
     static final int TOP_BOUND_SHIFT = 10;
 
@@ -838,17 +841,18 @@ public class ForkJoinPool extends AbstractExecutorService {
          */
         final void push(ForkJoinTask<?> task) {
             ForkJoinTask<?>[] a;
-            int s = top, d = s - base, cap, m;
+            int s = top, d, cap, m;
             ForkJoinPool p = pool;
             if ((a = array) != null && (cap = a.length) > 0) {
                 QA.setRelease(a, (m = cap - 1) & s, task);
                 top = s + 1;
-                if (d == m)
-                    growArray(false);
-                else if (QA.getAcquire(a, m & (s - 1)) == null && p != null) {
-                    VarHandle.fullFence();  // was empty
-                    p.signalWork(null);
+                if (((d = s - (int)BASE.getAcquire(this)) & ~1) == 0 &&
+                    p != null) {                 // size 0 or 1
+                    VarHandle.fullFence();
+                    p.signalWork();
                 }
+                else if (d == m)
+                    growArray(false);
             }
         }
 
@@ -859,16 +863,16 @@ public class ForkJoinPool extends AbstractExecutorService {
         final boolean lockedPush(ForkJoinTask<?> task) {
             ForkJoinTask<?>[] a;
             boolean signal = false;
-            int s = top, d = s - base, cap, m;
+            int s = top, b = base, cap, d;
             if ((a = array) != null && (cap = a.length) > 0) {
-                a[(m = (cap - 1)) & s] = task;
+                a[(cap - 1) & s] = task;
                 top = s + 1;
-                if (d == m)
+                if (b - s + cap - 1 == 0)
                     growArray(true);
                 else {
                     phase = 0; // full volatile unlock
-                    if (a[m & (s - 1)] == null)
-                        signal = true;   // was empty
+                    if (((s - base) & ~1) == 0) // size 0 or 1
+                        signal = true;
                 }
             }
             return signal;
@@ -1010,30 +1014,25 @@ public class ForkJoinPool extends AbstractExecutorService {
          * queue, up to bound n (to avoid infinite unfairness).
          */
         final void topLevelExec(ForkJoinTask<?> t, WorkQueue q, int n) {
-            int nstolen = 1;
-            for (int j = 0;;) {
-                if (t != null)
+            if (t != null && q != null) { // hoist checks
+                int nstolen = 1;
+                for (;;) {
                     t.doExec();
-                if (j++ <= n)
-                    t = nextLocalTask();
-                else {
-                    j = 0;
-                    t = null;
-                }
-                if (t == null) {
-                    if (q != null && (t = q.poll()) != null) {
-                        ++nstolen;
-                        j = 0;
-                    }
-                    else if (j != 0)
+                    if (n-- < 0)
                         break;
+                    else if ((t = nextLocalTask()) == null) {
+                        if ((t = q.poll()) == null)
+                            break;
+                        else
+                            ++nstolen;
+                    }
                 }
+                ForkJoinWorkerThread thread = owner;
+                nsteals += nstolen;
+                source = 0;
+                if (thread != null)
+                    thread.afterTopLevelExec();
             }
-            ForkJoinWorkerThread thread = owner;
-            nsteals += nstolen;
-            source = 0;
-            if (thread != null)
-                thread.afterTopLevelExec();
         }
 
         /**
@@ -1456,7 +1455,7 @@ public class ForkJoinPool extends AbstractExecutorService {
 
         if (!tryTerminate(false, false) &&            // possibly replace worker
             w != null && w.array != null)             // avoid repeated failures
-            signalWork(null);
+            signalWork();
 
         if (ex == null)                               // help clean on way out
             ForkJoinTask.helpExpungeStaleExceptions();
@@ -1466,9 +1465,8 @@ public class ForkJoinPool extends AbstractExecutorService {
 
     /**
      * Tries to create or release a worker if too few are running.
-     * @param q if non-null recheck if empty on CAS failure
      */
-    final void signalWork(WorkQueue q) {
+    final void signalWork() {
         for (;;) {
             long c; int sp; WorkQueue[] ws; int i; WorkQueue v;
             if ((c = ctl) >= 0L)                      // enough workers
@@ -1495,8 +1493,6 @@ public class ForkJoinPool extends AbstractExecutorService {
                         LockSupport.unpark(vt);
                     break;
                 }
-                else if (q != null && q.isEmpty())     // no need to retry
-                    break;
             }
         }
     }
@@ -1617,24 +1613,19 @@ public class ForkJoinPool extends AbstractExecutorService {
                 else if (rc <= 0 && (md & SHUTDOWN) != 0 &&
                          tryTerminate(false, false))
                     break;                        // quiescent shutdown
-                else if (w.phase < 0) {
-                    if (rc <= 0 && pred != 0 && phase == (int)c) {
-                        long nc = (UC_MASK & (c - TC_UNIT)) | (SP_MASK & pred);
-                        long d = keepAlive + System.currentTimeMillis();
-                        LockSupport.parkUntil(this, d);
-                        if (ctl == c &&           // drop on timeout if all idle
-                            d - System.currentTimeMillis() <= TIMEOUT_SLOP &&
-                            CTL.compareAndSet(this, c, nc)) {
-                            w.phase = QUIET;
-                            break;
-                        }
-                    }
-                    else {
-                        LockSupport.park(this);
-                        if (w.phase < 0)          // one spurious wakeup check
-                            LockSupport.park(this);
+                else if (rc <= 0 && pred != 0 && phase == (int)c) {
+                    long nc = (UC_MASK & (c - TC_UNIT)) | (SP_MASK & pred);
+                    long d = keepAlive + System.currentTimeMillis();
+                    LockSupport.parkUntil(this, d);
+                    if (ctl == c &&               // drop on timeout if all idle
+                        d - System.currentTimeMillis() <= TIMEOUT_SLOP &&
+                        CTL.compareAndSet(this, c, nc)) {
+                        w.phase = QUIET;
+                        break;
                     }
                 }
+                else if (w.phase < 0)
+                    LockSupport.park(this);       // OK if spuriously woken
                 w.source = 0;                     // disable signal
             }
         }
@@ -1650,8 +1641,8 @@ public class ForkJoinPool extends AbstractExecutorService {
         WorkQueue[] ws; int n;
         if ((ws = workQueues) != null && (n = ws.length) > 0 && w != null) {
             for (int m = n - 1, j = r & m;;) {
-                WorkQueue q; int b, s;
-                if ((q = ws[j]) != null && (s = q.top) != (b = q.base)) {
+                WorkQueue q; int b;
+                if ((q = ws[j]) != null && q.top != (b = q.base)) {
                     int qid = q.id;
                     ForkJoinTask<?>[] a; int cap, k; ForkJoinTask<?> t;
                     if ((a = q.array) != null && (cap = a.length) > 0) {
@@ -1660,10 +1651,10 @@ public class ForkJoinPool extends AbstractExecutorService {
                             QA.compareAndSet(a, k, t, null)) {
                             q.base = b;
                             w.source = qid;
-                            if (s != b && a[(cap - 1) & b] != null)
-                                signalWork(q);    // help signal if more tasks
+                            if (q.top - b > 0)
+                                signalWork();
                             w.topLevelExec(t, q,  // random fairness bound
-                                           (r | (1 << TOP_BOUND_SHIFT)) & SMASK);
+                                           r & ((n << TOP_BOUND_SHIFT) - 1));
                         }
                     }
                     return true;
@@ -1909,7 +1900,7 @@ public class ForkJoinPool extends AbstractExecutorService {
                 r = ThreadLocalRandom.advanceProbe(r);
             else {
                 if (q.lockedPush(task))
-                    signalWork(null);
+                    signalWork();
                 return;
             }
         }

src/java.base/share/classes/java/util/jar/Attributes.java

@@ -36,6 +36,8 @@ import java.util.Set;
 
 import sun.util.logging.PlatformLogger;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 /**
  * The Attributes class maps Manifest attribute names to associated string
  * values. Valid attribute names are case-insensitive, are restricted to
@@ -298,25 +300,16 @@ public class Attributes implements Map<Object,Object>, Cloneable {
      * Writes the current attributes to the specified data output stream.
      * XXX Need to handle UTF8 values and break up lines longer than 72 bytes
      */
-     @SuppressWarnings("deprecation")
-     void write(DataOutputStream os) throws IOException {
-         for (Entry<Object, Object> e : entrySet()) {
-             StringBuffer buffer = new StringBuffer(
-                                         ((Name) e.getKey()).toString());
-             buffer.append(": ");
-
-             String value = (String) e.getValue();
-             if (value != null) {
-                 byte[] vb = value.getBytes("UTF8");
-                 value = new String(vb, 0, 0, vb.length);
-             }
-             buffer.append(value);
-
-             Manifest.make72Safe(buffer);
-             buffer.append("\r\n");
-             os.writeBytes(buffer.toString());
-         }
-        os.writeBytes("\r\n");
+    void write(DataOutputStream out) throws IOException {
+        StringBuilder buffer = new StringBuilder(72);
+        for (Entry<Object, Object> e : entrySet()) {
+            buffer.setLength(0);
+            buffer.append(e.getKey().toString());
+            buffer.append(": ");
+            buffer.append(e.getValue());
+            Manifest.println72(out, buffer.toString());
+        }
+        Manifest.println(out); // empty line after individual section
     }
 
     /*
@@ -326,9 +319,9 @@ public class Attributes implements Map<Object,Object>, Cloneable {
      *
      * XXX Need to handle UTF8 values and break up lines longer than 72 bytes
      */
-    @SuppressWarnings("deprecation")
-    void writeMain(DataOutputStream out) throws IOException
-    {
+    void writeMain(DataOutputStream out) throws IOException {
+        StringBuilder buffer = new StringBuilder(72);
+
         // write out the *-Version header first, if it exists
         String vername = Name.MANIFEST_VERSION.toString();
         String version = getValue(vername);
@@ -338,7 +331,11 @@ public class Attributes implements Map<Object,Object>, Cloneable {
         }
 
         if (version != null) {
-            out.writeBytes(vername+": "+version+"\r\n");
+            buffer.append(vername);
+            buffer.append(": ");
+            buffer.append(version);
+            out.write(buffer.toString().getBytes(UTF_8));
+            Manifest.println(out);
         }
 
         // write out all attributes except for the version
@@ -346,34 +343,24 @@ public class Attributes implements Map<Object,Object>, Cloneable {
         for (Entry<Object, Object> e : entrySet()) {
             String name = ((Name) e.getKey()).toString();
             if ((version != null) && !(name.equalsIgnoreCase(vername))) {
-
-                StringBuffer buffer = new StringBuffer(name);
+                buffer.setLength(0);
+                buffer.append(name);
                 buffer.append(": ");
-
-                String value = (String) e.getValue();
-                if (value != null) {
-                    byte[] vb = value.getBytes("UTF8");
-                    value = new String(vb, 0, 0, vb.length);
-                }
-                buffer.append(value);
-
-                Manifest.make72Safe(buffer);
-                buffer.append("\r\n");
-                out.writeBytes(buffer.toString());
+                buffer.append(e.getValue());
+                Manifest.println72(out, buffer.toString());
             }
         }
-        out.writeBytes("\r\n");
+
+        Manifest.println(out); // empty line after main attributes section
     }
 
     /*
      * Reads attributes from the specified input stream.
-     * XXX Need to handle UTF8 values.
      */
     void read(Manifest.FastInputStream is, byte[] lbuf) throws IOException {
         read(is, lbuf, null, 0);
     }
 
-    @SuppressWarnings("deprecation")
     int read(Manifest.FastInputStream is, byte[] lbuf, String filename, int lineNumber) throws IOException {
         String name = null, value;
         byte[] lastline = null;
@@ -409,7 +396,7 @@ public class Attributes implements Map<Object,Object>, Cloneable {
                     lastline = buf;
                     continue;
                 }
-                value = new String(buf, 0, buf.length, "UTF8");
+                value = new String(buf, 0, buf.length, UTF_8);
                 lastline = null;
             } else {
                 while (lbuf[i++] != ':') {
@@ -422,13 +409,13 @@ public class Attributes implements Map<Object,Object>, Cloneable {
                     throw new IOException("invalid header field ("
                                 + Manifest.getErrorPosition(filename, lineNumber) + ")");
                 }
-                name = new String(lbuf, 0, 0, i - 2);
+                name = new String(lbuf, 0, i - 2, UTF_8);
                 if (is.peek() == ' ') {
                     lastline = new byte[len - i];
                     System.arraycopy(lbuf, i, lastline, 0, len - i);
                     continue;
                 }
-                value = new String(lbuf, i, len - i, "UTF8");
+                value = new String(lbuf, i, len - i, UTF_8);
             }
             try {
                 if ((putValue(name, value) != null) && (!lineContinued)) {

src/java.base/share/classes/java/util/jar/Manifest.java

@@ -35,6 +35,8 @@ import java.util.Map;
 
 import sun.security.util.SecurityProperties;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 /**
  * The Manifest class is used to maintain Manifest entry names and their
  * associated Attributes. There are main Manifest Attributes as well as
@@ -197,31 +199,28 @@ public class Manifest implements Cloneable {
      * @exception IOException if an I/O error has occurred
      * @see #getMainAttributes
      */
-    @SuppressWarnings("deprecation")
     public void write(OutputStream out) throws IOException {
         DataOutputStream dos = new DataOutputStream(out);
         // Write out the main attributes for the manifest
         attr.writeMain(dos);
         // Now write out the per-entry attributes
+        StringBuilder buffer = entries.isEmpty() ? null : new StringBuilder(72);
         for (Map.Entry<String, Attributes> e : entries.entrySet()) {
-            StringBuffer buffer = new StringBuffer("Name: ");
-            String value = e.getKey();
-            if (value != null) {
-                byte[] vb = value.getBytes("UTF8");
-                value = new String(vb, 0, 0, vb.length);
-            }
-            buffer.append(value);
-            make72Safe(buffer);
-            buffer.append("\r\n");
-            dos.writeBytes(buffer.toString());
+            buffer.setLength(0);
+            buffer.append("Name: ");
+            buffer.append(e.getKey());
+            println72(dos, buffer.toString());
             e.getValue().write(dos);
         }
         dos.flush();
     }
 
     /**
-     * Adds line breaks to enforce a maximum 72 bytes per line.
+     * Adds line breaks to enforce a maximum of 72 bytes per line.
+     *
+     * @deprecation Replaced with {@link #println72}.
      */
+    @Deprecated(since = "13")
     static void make72Safe(StringBuffer line) {
         int length = line.length();
         int index = 72;
@@ -230,7 +229,38 @@ public class Manifest implements Cloneable {
             index += 74; // + line width + line break ("\r\n")
             length += 3; // + line break ("\r\n") and space
         }
-        return;
+    }
+
+    /**
+     * Writes {@code line} to {@code out} with line breaks and continuation
+     * spaces within the limits of 72 bytes of contents per line followed
+     * by a line break.
+     */
+    static void println72(OutputStream out, String line) throws IOException {
+        if (!line.isEmpty()) {
+            byte[] lineBytes = line.getBytes(UTF_8);
+            int length = lineBytes.length;
+            // first line can hold one byte more than subsequent lines which
+            // start with a continuation line break space
+            out.write(lineBytes[0]);
+            int pos = 1;
+            while (length - pos > 71) {
+                out.write(lineBytes, pos, 71);
+                pos += 71;
+                println(out);
+                out.write(' ');
+            }
+            out.write(lineBytes, pos, length - pos);
+        }
+        println(out);
+    }
+
+    /**
+     * Writes a line break to {@code out}.
+     */
+    static void println(OutputStream out) throws IOException {
+        out.write('\r');
+        out.write('\n');
     }
 
     static String getErrorPosition(String filename, final int lineNumber) {
@@ -304,7 +334,7 @@ public class Manifest implements Cloneable {
                     lastline = buf;
                     continue;
                 }
-                name = new String(buf, 0, buf.length, "UTF8");
+                name = new String(buf, 0, buf.length, UTF_8);
                 lastline = null;
             }
             Attributes attr = getAttributes(name);
@@ -330,7 +360,7 @@ public class Manifest implements Cloneable {
             toLower(lbuf[2]) == 'm' && toLower(lbuf[3]) == 'e' &&
             lbuf[4] == ':' && lbuf[5] == ' ') {
             try {
-                return new String(lbuf, 6, len - 6, "UTF8");
+                return new String(lbuf, 6, len - 6, UTF_8);
             }
             catch (Exception e) {
             }

src/java.base/share/classes/java/util/jar/Pack200.java

@@ -112,7 +112,7 @@ public abstract class Pack200 {
     /**
      * Obtain new instance of a class that implements Packer.
      * <ul>
-     * <li><p>If the system property {@code java.util.jar.Pack200.Packer}
+     * <li><p>If the system property {@systemProperty java.util.jar.Pack200.Packer}
      * is defined, then the value is taken to be the fully-qualified name
      * of a concrete implementation class, which must implement Packer.
      * This class is loaded and instantiated.  If this process fails
@@ -138,7 +138,7 @@ public abstract class Pack200 {
     /**
      * Obtain new instance of a class that implements Unpacker.
      * <ul>
-     * <li><p>If the system property {@code java.util.jar.Pack200.Unpacker}
+     * <li><p>If the system property {@systemProperty java.util.jar.Pack200.Unpacker}
      * is defined, then the value is taken to be the fully-qualified
      * name of a concrete implementation class, which must implement Unpacker.
      * The class is loaded and instantiated.  If this process fails

src/java.base/share/classes/java/util/regex/Pattern.java

@@ -1390,7 +1390,7 @@ public final class Pattern
         localTCNCount = 0;
 
         // if length > 0, the Pattern is lazily compiled
-        if (pattern.length() == 0) {
+        if (pattern.isEmpty()) {
             root = new Start(lastAccept);
             matchRoot = lastAccept;
             compiled = true;
@@ -1423,7 +1423,7 @@ public final class Pattern
         localCount = 0;
         localTCNCount = 0;
 
-        if (pattern.length() > 0) {
+        if (!pattern.isEmpty()) {
             compile();
         } else {
             root = new Start(lastAccept);

src/java.base/share/classes/java/util/spi/LocaleServiceProvider.java

@@ -113,7 +113,7 @@ import java.util.Locale;
  * described above as if the locale was not supported.
  * <p>
  * The search order of locale sensitive services can
- * be configured by using the "java.locale.providers" system property.
+ * be configured by using the {@systemProperty java.locale.providers} system property.
  * This system property declares the user's preferred order for looking up
  * the locale sensitive services separated by a comma. It is only read at
  * the Java runtime startup, so the later call to System.setProperty() won't

src/java.base/share/classes/javax/crypto/Cipher.java

@@ -341,7 +341,7 @@ public class Cipher {
             throw new NoSuchAlgorithmException("Invalid transformation " +
                                            "format:" + transformation);
         }
-        if ((parts[0] == null) || (parts[0].length() == 0)) {
+        if ((parts[0] == null) || (parts[0].isEmpty())) {
             throw new NoSuchAlgorithmException("Invalid transformation:" +
                                    "algorithm not specified-"
                                    + transformation);
@@ -445,10 +445,10 @@ public class Cipher {
         String alg = parts[0];
         String mode = parts[1];
         String pad = parts[2];
-        if ((mode != null) && (mode.length() == 0)) {
+        if ((mode != null) && (mode.isEmpty())) {
             mode = null;
         }
-        if ((pad != null) && (pad.length() == 0)) {
+        if ((pad != null) && (pad.isEmpty())) {
             pad = null;
         }
 
@@ -634,7 +634,7 @@ public class Cipher {
         if ((transformation == null) || transformation.isEmpty()) {
             throw new NoSuchAlgorithmException("Null or empty transformation");
         }
-        if ((provider == null) || (provider.length() == 0)) {
+        if ((provider == null) || (provider.isEmpty())) {
             throw new IllegalArgumentException("Missing provider");
         }
         Provider p = Security.getProvider(provider);

src/java.base/share/classes/javax/crypto/SealedObject.java

@@ -337,7 +337,7 @@ public class SealedObject implements Serializable {
         if (key == null) {
             throw new NullPointerException("key is null");
         }
-        if (provider == null || provider.length() == 0) {
+        if (provider == null || provider.isEmpty()) {
             throw new IllegalArgumentException("missing provider");
         }
 

src/java.base/share/classes/javax/net/ssl/SSLSession.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -187,7 +187,7 @@ public interface SSLSession {
      * Removes the object bound to the given name in the session's
      * application layer data.  Does nothing if there is no object
      * bound to the given name.  If the bound existing object
-     * implements the {@code SessionBindingListener} interface,
+     * implements the {@code SSLSessionBindingListener} interface,
      * it is notified appropriately.
      * <p>
      * For security reasons, the same named values may not be

src/java.base/share/classes/javax/net/ssl/SSLSocketFactory.java

@@ -133,7 +133,7 @@ public abstract class SSLSocketFactory extends SocketFactory
                 String s = java.security.Security.getProperty(name);
                 if (s != null) {
                     s = s.trim();
-                    if (s.length() == 0) {
+                    if (s.isEmpty()) {
                         s = null;
                     }
                 }

src/java.base/share/classes/javax/security/auth/PrivateCredentialPermission.java

@@ -312,7 +312,7 @@ public final class PrivateCredentialPermission extends Permission {
 
     private void init(String name) {
 
-        if (name == null || name.trim().length() == 0) {
+        if (name == null || name.trim().isEmpty()) {
             throw new IllegalArgumentException("invalid empty name");
         }
 

src/java.base/share/classes/javax/security/auth/callback/ChoiceCallback.java

@@ -98,13 +98,13 @@ public class ChoiceCallback implements Callback, java.io.Serializable {
     public ChoiceCallback(String prompt, String[] choices,
                 int defaultChoice, boolean multipleSelectionsAllowed) {
 
-        if (prompt == null || prompt.length() == 0 ||
+        if (prompt == null || prompt.isEmpty() ||
             choices == null || choices.length == 0 ||
             defaultChoice < 0 || defaultChoice >= choices.length)
             throw new IllegalArgumentException();
 
         for (int i = 0; i < choices.length; i++) {
-            if (choices[i] == null || choices[i].length() == 0)
+            if (choices[i] == null || choices[i].isEmpty())
                 throw new IllegalArgumentException();
         }
 

src/java.base/share/classes/javax/security/auth/callback/ConfirmationCallback.java

@@ -248,7 +248,7 @@ public class ConfirmationCallback implements Callback, java.io.Serializable {
             throw new IllegalArgumentException();
 
         for (int i = 0; i < options.length; i++) {
-            if (options[i] == null || options[i].length() == 0)
+            if (options[i] == null || options[i].isEmpty())
                 throw new IllegalArgumentException();
         }
 
@@ -294,7 +294,7 @@ public class ConfirmationCallback implements Callback, java.io.Serializable {
     public ConfirmationCallback(String prompt, int messageType,
                 int optionType, int defaultOption) {
 
-        if (prompt == null || prompt.length() == 0 ||
+        if (prompt == null || prompt.isEmpty() ||
             messageType < INFORMATION || messageType > ERROR ||
             optionType < YES_NO_OPTION || optionType > OK_CANCEL_OPTION)
             throw new IllegalArgumentException();
@@ -357,14 +357,14 @@ public class ConfirmationCallback implements Callback, java.io.Serializable {
     public ConfirmationCallback(String prompt, int messageType,
                 String[] options, int defaultOption) {
 
-        if (prompt == null || prompt.length() == 0 ||
+        if (prompt == null || prompt.isEmpty() ||
             messageType < INFORMATION || messageType > ERROR ||
             options == null || options.length == 0 ||
             defaultOption < 0 || defaultOption >= options.length)
             throw new IllegalArgumentException();
 
         for (int i = 0; i < options.length; i++) {
-            if (options[i] == null || options[i].length() == 0)
+            if (options[i] == null || options[i].isEmpty())
                 throw new IllegalArgumentException();
         }
 

src/java.base/share/classes/javax/security/auth/callback/NameCallback.java

@@ -62,7 +62,7 @@ public class NameCallback implements Callback, java.io.Serializable {
      *                  or if {@code prompt} has a length of 0.
      */
     public NameCallback(String prompt) {
-        if (prompt == null || prompt.length() == 0)
+        if (prompt == null || prompt.isEmpty())
             throw new IllegalArgumentException();
         this.prompt = prompt;
     }
@@ -82,8 +82,8 @@ public class NameCallback implements Callback, java.io.Serializable {
      *                  or if {@code defaultName} has a length of 0.
      */
     public NameCallback(String prompt, String defaultName) {
-        if (prompt == null || prompt.length() == 0 ||
-            defaultName == null || defaultName.length() == 0)
+        if (prompt == null || prompt.isEmpty() ||
+            defaultName == null || defaultName.isEmpty())
             throw new IllegalArgumentException();
 
         this.prompt = prompt;

src/java.base/share/classes/javax/security/auth/callback/PasswordCallback.java

@@ -67,7 +67,7 @@ public class PasswordCallback implements Callback, java.io.Serializable {
      *                  if {@code prompt} has a length of 0.
      */
     public PasswordCallback(String prompt, boolean echoOn) {
-        if (prompt == null || prompt.length() == 0)
+        if (prompt == null || prompt.isEmpty())
             throw new IllegalArgumentException();
 
         this.prompt = prompt;

src/java.base/share/classes/javax/security/auth/callback/TextInputCallback.java

@@ -63,7 +63,7 @@ public class TextInputCallback implements Callback, java.io.Serializable {
      *                  or if {@code prompt} has a length of 0.
      */
     public TextInputCallback(String prompt) {
-        if (prompt == null || prompt.length() == 0)
+        if (prompt == null || prompt.isEmpty())
             throw new IllegalArgumentException();
         this.prompt = prompt;
     }
@@ -83,8 +83,8 @@ public class TextInputCallback implements Callback, java.io.Serializable {
      *                  or if {@code defaultText} has a length of 0.
      */
     public TextInputCallback(String prompt, String defaultText) {
-        if (prompt == null || prompt.length() == 0 ||
-            defaultText == null || defaultText.length() == 0)
+        if (prompt == null || prompt.isEmpty() ||
+            defaultText == null || defaultText.isEmpty())
             throw new IllegalArgumentException();
 
         this.prompt = prompt;

src/java.base/share/classes/javax/security/auth/callback/TextOutputCallback.java

@@ -74,7 +74,7 @@ public class TextOutputCallback implements Callback, java.io.Serializable {
     public TextOutputCallback(int messageType, String message) {
         if ((messageType != INFORMATION &&
                 messageType != WARNING && messageType != ERROR) ||
-            message == null || message.length() == 0)
+            message == null || message.isEmpty())
             throw new IllegalArgumentException();
 
         this.messageType = messageType;