8258422: Cleanup unnecessary null comparison before instanceof check in java.base

Reviewed-by: chegar, aefimov

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

@@ -2190,8 +2190,8 @@ public class File
      *          {@code false} otherwise
      */
     public boolean equals(Object obj) {
-        if ((obj != null) && (obj instanceof File)) {
+        if (obj instanceof File file) {
-            return compareTo((File)obj) == 0;
+            return compareTo(file) == 0;
         }
         return false;
     }

src/java.base/share/classes/java/lang/reflect/Constructor.java

@@ -308,8 +308,7 @@ public final class Constructor<T> extends Executable {
      * same formal parameter types.
      */
     public boolean equals(Object obj) {
-        if (obj != null && obj instanceof Constructor) {
+        if (obj instanceof Constructor<?> other) {
-            Constructor<?> other = (Constructor<?>)obj;
             if (getDeclaringClass() == other.getDeclaringClass()) {
                 return equalParamTypes(parameterTypes, other.parameterTypes);
             }

src/java.base/share/classes/java/lang/reflect/Field.java

@@ -279,8 +279,7 @@ class Field extends AccessibleObject implements Member {
      * and type.
      */
     public boolean equals(Object obj) {
-        if (obj != null && obj instanceof Field) {
+        if (obj instanceof Field other) {
-            Field other = (Field)obj;
             return (getDeclaringClass() == other.getDeclaringClass())
                 && (getName() == other.getName())
                 && (getType() == other.getType());

src/java.base/share/classes/java/lang/reflect/Method.java

@@ -358,8 +358,7 @@ public final class Method extends Executable {
      * and formal parameter types and return type.
      */
     public boolean equals(Object obj) {
-        if (obj != null && obj instanceof Method) {
+        if (obj instanceof Method other) {
-            Method other = (Method)obj;
             if ((getDeclaringClass() == other.getDeclaringClass())
                 && (getName() == other.getName())) {
                 if (!returnType.equals(other.getReturnType()))

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

@@ -235,9 +235,9 @@ abstract class AbstractPlainDatagramSocketImpl extends DatagramSocketImpl
 
     protected void joinGroup(SocketAddress mcastaddr, NetworkInterface netIf)
         throws IOException {
-        if (mcastaddr == null || !(mcastaddr instanceof InetSocketAddress))
+        if (!(mcastaddr instanceof InetSocketAddress addr))
             throw new IllegalArgumentException("Unsupported address type");
-        join(((InetSocketAddress)mcastaddr).getAddress(), netIf);
+        join(addr.getAddress(), netIf);
     }
 
     protected abstract void join(InetAddress inetaddr, NetworkInterface netIf)
@@ -253,9 +253,9 @@ abstract class AbstractPlainDatagramSocketImpl extends DatagramSocketImpl
      */
     protected void leaveGroup(SocketAddress mcastaddr, NetworkInterface netIf)
         throws IOException {
-        if (mcastaddr == null || !(mcastaddr instanceof InetSocketAddress))
+        if (!(mcastaddr instanceof InetSocketAddress addr))
             throw new IllegalArgumentException("Unsupported address type");
-        leave(((InetSocketAddress)mcastaddr).getAddress(), netIf);
+        leave(addr.getAddress(), netIf);
     }
 
     protected abstract void leave(InetAddress inetaddr, NetworkInterface netIf)
@@ -292,7 +292,7 @@ abstract class AbstractPlainDatagramSocketImpl extends DatagramSocketImpl
              * PlainSocketImpl.setOption().
              */
          case SO_TIMEOUT:
-             if (o == null || !(o instanceof Integer)) {
+             if (!(o instanceof Integer)) {
                  throw new SocketException("bad argument for SO_TIMEOUT");
              }
              int tmp = ((Integer) o).intValue();
@@ -301,18 +301,18 @@ abstract class AbstractPlainDatagramSocketImpl extends DatagramSocketImpl
              timeout = tmp;
              return;
          case IP_TOS:
-             if (o == null || !(o instanceof Integer)) {
+             if (!(o instanceof Integer)) {
                  throw new SocketException("bad argument for IP_TOS");
              }
              trafficClass = ((Integer)o).intValue();
              break;
          case SO_REUSEADDR:
-             if (o == null || !(o instanceof Boolean)) {
+             if (!(o instanceof Boolean)) {
                  throw new SocketException("bad argument for SO_REUSEADDR");
              }
              break;
          case SO_BROADCAST:
-             if (o == null || !(o instanceof Boolean)) {
+             if (!(o instanceof Boolean)) {
                  throw new SocketException("bad argument for SO_BROADCAST");
              }
              break;
@@ -320,26 +320,26 @@ abstract class AbstractPlainDatagramSocketImpl extends DatagramSocketImpl
              throw new SocketException("Cannot re-bind Socket");
          case SO_RCVBUF:
          case SO_SNDBUF:
-             if (o == null || !(o instanceof Integer) ||
+             if (!(o instanceof Integer) ||
                  ((Integer)o).intValue() < 0) {
                  throw new SocketException("bad argument for SO_SNDBUF or " +
                                            "SO_RCVBUF");
              }
              break;
          case IP_MULTICAST_IF:
-             if (o == null || !(o instanceof InetAddress))
+             if (!(o instanceof InetAddress))
                  throw new SocketException("bad argument for IP_MULTICAST_IF");
              break;
          case IP_MULTICAST_IF2:
-             if (o == null || !(o instanceof NetworkInterface))
+             if (!(o instanceof NetworkInterface))
                  throw new SocketException("bad argument for IP_MULTICAST_IF2");
              break;
          case IP_MULTICAST_LOOP:
-             if (o == null || !(o instanceof Boolean))
+             if (!(o instanceof Boolean))
                  throw new SocketException("bad argument for IP_MULTICAST_LOOP");
              break;
          case SO_REUSEPORT:
-             if (o == null || !(o instanceof Boolean)) {
+             if (!(o instanceof Boolean)) {
                  throw new SocketException("bad argument for SO_REUSEPORT");
              }
              if (!supportedOptions().contains(StandardSocketOptions.SO_REUSEPORT)) {

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

@@ -213,9 +213,8 @@ abstract class AbstractPlainSocketImpl extends SocketImpl implements PlatformSoc
             throws IOException {
         boolean connected = false;
         try {
-            if (address == null || !(address instanceof InetSocketAddress))
+            if (!(address instanceof InetSocketAddress addr))
                 throw new IllegalArgumentException("unsupported address type");
-            InetSocketAddress addr = (InetSocketAddress) address;
             if (addr.isUnresolved())
                 throw new UnknownHostException(addr.getHostName());
             // recording this.address as supplied by caller before calling connect
@@ -259,7 +258,7 @@ abstract class AbstractPlainSocketImpl extends SocketImpl implements PlatformSoc
              * PlainSocketImpl.setOption().
              */
         case SO_LINGER:
-            if (val == null || (!(val instanceof Integer) && !(val instanceof Boolean)))
+            if (!(val instanceof Integer) && !(val instanceof Boolean))
                 throw new SocketException("Bad parameter for option");
             if (val instanceof Boolean) {
                 /* true only if disabling - enabling should be Integer */
@@ -267,7 +266,7 @@ abstract class AbstractPlainSocketImpl extends SocketImpl implements PlatformSoc
             }
             break;
         case SO_TIMEOUT:
-            if (val == null || (!(val instanceof Integer)))
+            if (!(val instanceof Integer))
                 throw new SocketException("Bad parameter for SO_TIMEOUT");
             int tmp = ((Integer) val).intValue();
             if (tmp < 0)
@@ -275,7 +274,7 @@ abstract class AbstractPlainSocketImpl extends SocketImpl implements PlatformSoc
             timeout = tmp;
             break;
         case IP_TOS:
-             if (val == null || !(val instanceof Integer)) {
+             if (!(val instanceof Integer)) {
                  throw new SocketException("bad argument for IP_TOS");
              }
              trafficClass = ((Integer)val).intValue();
@@ -283,35 +282,35 @@ abstract class AbstractPlainSocketImpl extends SocketImpl implements PlatformSoc
         case SO_BINDADDR:
             throw new SocketException("Cannot re-bind socket");
         case TCP_NODELAY:
-            if (val == null || !(val instanceof Boolean))
+            if (!(val instanceof Boolean))
                 throw new SocketException("bad parameter for TCP_NODELAY");
             on = ((Boolean)val).booleanValue();
             break;
         case SO_SNDBUF:
         case SO_RCVBUF:
-            if (val == null || !(val instanceof Integer) ||
+            if (!(val instanceof Integer) ||
                 !(((Integer)val).intValue() > 0)) {
                 throw new SocketException("bad parameter for SO_SNDBUF " +
                                           "or SO_RCVBUF");
             }
             break;
         case SO_KEEPALIVE:
-            if (val == null || !(val instanceof Boolean))
+            if (!(val instanceof Boolean))
                 throw new SocketException("bad parameter for SO_KEEPALIVE");
             on = ((Boolean)val).booleanValue();
             break;
         case SO_OOBINLINE:
-            if (val == null || !(val instanceof Boolean))
+            if (!(val instanceof Boolean))
                 throw new SocketException("bad parameter for SO_OOBINLINE");
             on = ((Boolean)val).booleanValue();
             break;
         case SO_REUSEADDR:
-            if (val == null || !(val instanceof Boolean))
+            if (!(val instanceof Boolean))
                 throw new SocketException("bad parameter for SO_REUSEADDR");
             on = ((Boolean)val).booleanValue();
             break;
         case SO_REUSEPORT:
-            if (val == null || !(val instanceof Boolean))
+            if (!(val instanceof Boolean))
                 throw new SocketException("bad parameter for SO_REUSEPORT");
             if (!supportedOptions().contains(StandardSocketOptions.SO_REUSEPORT))
                 throw new UnsupportedOperationException("unsupported option");

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

@@ -352,9 +352,8 @@ class DatagramPacket {
      * @since   1.4
      */
     public synchronized void setSocketAddress(SocketAddress address) {
-        if (address == null || !(address instanceof InetSocketAddress))
+        if (!(address instanceof InetSocketAddress addr))
             throw new IllegalArgumentException("unsupported address type");
-        InetSocketAddress addr = (InetSocketAddress) address;
         if (addr.isUnresolved())
             throw new IllegalArgumentException("unresolved address");
         setAddress(addr.getAddress());

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

@@ -102,9 +102,8 @@ import java.util.Set;
     protected void connect(SocketAddress endpoint, int timeout)
         throws IOException
     {
-        if (endpoint == null || !(endpoint instanceof InetSocketAddress))
+        if (!(endpoint instanceof InetSocketAddress epoint))
             throw new IllegalArgumentException("Unsupported address type");
-        final InetSocketAddress epoint = (InetSocketAddress)endpoint;
         String destHost = epoint.isUnresolved() ? epoint.getHostName()
                                                 : epoint.getAddress().getHostAddress();
         final int destPort = epoint.getPort();

src/java.base/share/classes/java/net/Inet4Address.java

@@ -352,8 +352,8 @@ class Inet4Address extends InetAddress {
      * @see     java.net.InetAddress#getAddress()
      */
     public boolean equals(Object obj) {
-        return (obj != null) && (obj instanceof Inet4Address) &&
+        return (obj instanceof Inet4Address inet4Address) &&
-            (((InetAddress)obj).holder().getAddress() == holder().getAddress());
+            inet4Address.holder().getAddress() == holder().getAddress();
     }
 
     // Utilities

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

@@ -878,13 +878,11 @@ class Inet6Address extends InetAddress {
      */
     @Override
     public boolean equals(Object obj) {
-        if (obj == null || !(obj instanceof Inet6Address))
+        if (obj instanceof Inet6Address inetAddr) {
-            return false;
-
-        Inet6Address inetAddr = (Inet6Address)obj;
-
             return holder6.equals(inetAddr.holder6);
         }
+        return false;
+    }
 
     /**
      * Utility routine to check if the InetAddress is an

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

@@ -119,9 +119,8 @@ public class InetSocketAddress
 
         @Override
         public final boolean equals(Object obj) {
-            if (obj == null || !(obj instanceof InetSocketAddressHolder))
+            if (!(obj instanceof InetSocketAddressHolder that))
                 return false;
-            InetSocketAddressHolder that = (InetSocketAddressHolder)obj;
             boolean sameIP;
             if (addr != null)
                 sameIP = addr.equals(that.addr);
@@ -409,9 +408,10 @@ public class InetSocketAddress
      */
     @Override
     public final boolean equals(Object obj) {
-        if (obj == null || !(obj instanceof InetSocketAddress))
+        if (obj instanceof InetSocketAddress addr) {
+            return holder.equals(addr.holder);
+        }
         return false;
-        return holder.equals(((InetSocketAddress) obj).holder);
     }
 
     /**

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

@@ -801,19 +801,19 @@ final class NetMulticastSocket extends MulticastSocket {
         if (isClosed())
             throw new SocketException("Socket is closed");
 
-        if (mcastaddr == null || !(mcastaddr instanceof InetSocketAddress))
+        if (!(mcastaddr instanceof InetSocketAddress addr))
             throw new IllegalArgumentException("Unsupported address type");
 
         if (oldImpl)
             throw new UnsupportedOperationException();
 
-        checkAddress(((InetSocketAddress)mcastaddr).getAddress(), "joinGroup");
+        checkAddress(addr.getAddress(), "joinGroup");
         SecurityManager security = System.getSecurityManager();
         if (security != null) {
-            security.checkMulticast(((InetSocketAddress)mcastaddr).getAddress());
+            security.checkMulticast(addr.getAddress());
         }
 
-        if (!((InetSocketAddress)mcastaddr).getAddress().isMulticastAddress()) {
+        if (!addr.getAddress().isMulticastAddress()) {
             throw new SocketException("Not a multicast address");
         }
 
@@ -826,19 +826,19 @@ final class NetMulticastSocket extends MulticastSocket {
         if (isClosed())
             throw new SocketException("Socket is closed");
 
-        if (mcastaddr == null || !(mcastaddr instanceof InetSocketAddress))
+        if (!(mcastaddr instanceof InetSocketAddress addr))
             throw new IllegalArgumentException("Unsupported address type");
 
         if (oldImpl)
             throw new UnsupportedOperationException();
 
-        checkAddress(((InetSocketAddress)mcastaddr).getAddress(), "leaveGroup");
+        checkAddress(addr.getAddress(), "leaveGroup");
         SecurityManager security = System.getSecurityManager();
         if (security != null) {
-            security.checkMulticast(((InetSocketAddress)mcastaddr).getAddress());
+            security.checkMulticast(addr.getAddress());
         }
 
-        if (!((InetSocketAddress)mcastaddr).getAddress().isMulticastAddress()) {
+        if (!addr.getAddress().isMulticastAddress()) {
             throw new SocketException("Not a multicast address");
         }
 

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

@@ -146,9 +146,8 @@ public class Proxy {
      * @see java.net.InetSocketAddress#equals(java.lang.Object)
      */
     public final boolean equals(Object obj) {
-        if (obj == null || !(obj instanceof Proxy))
+        if (!(obj instanceof Proxy p))
             return false;
-        Proxy p = (Proxy) obj;
         if (p.type() == type()) {
             if (address() == null) {
                 return (p.address() == null);

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

@@ -272,9 +272,8 @@ class SocksSocketImpl extends DelegatingSocketImpl implements SocksConsts {
         }
 
         SecurityManager security = System.getSecurityManager();
-        if (endpoint == null || !(endpoint instanceof InetSocketAddress))
+        if (!(endpoint instanceof InetSocketAddress epoint))
             throw new IllegalArgumentException("Unsupported address type");
-        InetSocketAddress epoint = (InetSocketAddress) endpoint;
         if (security != null) {
             if (epoint.isUnresolved())
                 security.checkConnect(epoint.getHostName(),

src/java.base/share/classes/java/nio/file/attribute/AclEntry.java

@@ -342,9 +342,8 @@ public final class AclEntry {
     public boolean equals(Object ob) {
         if (ob == this)
             return true;
-        if (ob == null || !(ob instanceof AclEntry))
+        if (!(ob instanceof AclEntry other))
             return false;
-        AclEntry other = (AclEntry)ob;
         if (this.type != other.type)
             return false;
         if (!this.who.equals(other.who))

src/java.base/share/classes/jdk/internal/misc/Signal.java

@@ -95,18 +95,17 @@ public final class Signal {
     /**
      * Compares the equality of two <code>Signal</code> objects.
      *
-     * @param other the object to compare with.
+     * @param obj the object to compare with.
      * @return whether two <code>Signal</code> objects are equal.
      */
-    public boolean equals(Object other) {
+    public boolean equals(Object obj) {
-        if (this == other) {
+        if (this == obj) {
             return true;
         }
-        if (other == null || !(other instanceof Signal)) {
+        if (obj instanceof Signal other) {
-            return false;
+            return name.equals(other.name) && (number == other.number);
         }
-        Signal other1 = (Signal)other;
+        return false;
-        return name.equals(other1.name) && (number == other1.number);
     }
 
     /**

src/java.base/share/classes/sun/net/www/protocol/http/Negotiator.java

@@ -66,8 +66,8 @@ public abstract class Negotiator {
         } catch (ReflectiveOperationException roe) {
             finest(roe);
             Throwable t = roe.getCause();
-            if (t != null && t instanceof Exception)
+            if (t instanceof Exception exception)
-                finest((Exception)t);
+                finest(exception);
             return null;
         }
     }

src/java.base/share/classes/sun/net/www/protocol/https/HttpsClient.java

@@ -426,7 +426,7 @@ final class HttpsClient extends HttpClient
             // unconnected sockets have not been implemented.
             //
             Throwable t = se.getCause();
-            if (t != null && t instanceof UnsupportedOperationException) {
+            if (t instanceof UnsupportedOperationException) {
                 return super.createSocket();
             } else {
                 throw se;

src/java.base/share/classes/sun/nio/ch/DatagramSocketAdaptor.java

@@ -504,9 +504,9 @@ public class DatagramSocketAdaptor
      * @throws SocketException if group is not a multicast address
      */
     private static InetAddress checkGroup(SocketAddress mcastaddr) throws SocketException {
-        if (mcastaddr == null || !(mcastaddr instanceof InetSocketAddress))
+        if (!(mcastaddr instanceof InetSocketAddress addr))
             throw new IllegalArgumentException("Unsupported address type");
-        InetAddress group = ((InetSocketAddress) mcastaddr).getAddress();
+        InetAddress group = addr.getAddress();
         if (group == null)
             throw new IllegalArgumentException("Unresolved address");
         if (!group.isMulticastAddress())

src/java.base/share/classes/sun/nio/fs/PollingWatchService.java

@@ -149,8 +149,8 @@ class PollingWatchService
                 });
         } catch (PrivilegedActionException pae) {
             Throwable cause = pae.getCause();
-            if (cause != null && cause instanceof IOException)
+            if (cause instanceof IOException ioe)
-                throw (IOException)cause;
+                throw ioe;
             throw new AssertionError(pae);
         }
     }

src/java.base/unix/classes/sun/nio/fs/UnixPath.java

@@ -762,8 +762,8 @@ class UnixPath implements Path {
 
     @Override
     public boolean equals(Object ob) {
-        if ((ob != null) && (ob instanceof UnixPath)) {
+        if (ob instanceof UnixPath path) {
-            return compareTo((Path)ob) == 0;
+            return compareTo(path) == 0;
         }
         return false;
     }

src/java.base/windows/classes/sun/nio/fs/WindowsPath.java

@@ -798,8 +798,8 @@ class WindowsPath implements Path {
 
     @Override
     public boolean equals(Object obj) {
-        if ((obj != null) && (obj instanceof WindowsPath)) {
+        if (obj instanceof WindowsPath path) {
-            return compareTo((Path)obj) == 0;
+            return compareTo(path) == 0;
         }
         return false;
     }