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Mikael Vidstedt 2019-07-12 02:50:43 -07:00
commit cfcd0223a9
28 changed files with 1882 additions and 849 deletions
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113
src/java.base/share/classes/javax/crypto/CipherSpi.java
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2018, 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
@ -761,78 +761,87 @@ public abstract class CipherSpi {
+ " bytes of space in output buffer");
}
// detecting input and output buffer overlap may be tricky
// we can only write directly into output buffer when we
// are 100% sure it's safe to do so
boolean a1 = input.hasArray();
boolean a2 = output.hasArray();
int total = 0;
byte[] inArray, outArray;
if (a2) { // output has an accessible byte[]
outArray = output.array();
int outPos = output.position();
int outOfs = output.arrayOffset() + outPos;
if (a1) { // input also has an accessible byte[]
inArray = input.array();
int inOfs = input.arrayOffset() + inPos;
if (a1) { // input has an accessible byte[]
byte[] inArray = input.array();
int inOfs = input.arrayOffset() + inPos;
if (a2) { // output has an accessible byte[]
byte[] outArray = output.array();
int outPos = output.position();
int outOfs = output.arrayOffset() + outPos;
// check array address and offsets and use temp output buffer
// if output offset is larger than input offset and
// falls within the range of input data
boolean useTempOut = false;
if (inArray == outArray &&
((inOfs < outOfs) && (outOfs < inOfs + inLen))) {
useTempOut = true;
outArray = new byte[outLenNeeded];
outOfs = 0;
}
if (isUpdate) {
total = engineUpdate(inArray, inOfs, inLen, outArray, outOfs);
} else {
total = engineDoFinal(inArray, inOfs, inLen, outArray, outOfs);
}
if (useTempOut) {
output.put(outArray, outOfs, total);
} else {
// adjust output position manually
output.position(outPos + total);
}
// adjust input position manually
input.position(inLimit);
} else { // input does not have accessible byte[]
inArray = new byte[getTempArraySize(inLen)];
do {
int chunk = Math.min(inLen, inArray.length);
if (chunk > 0) {
input.get(inArray, 0, chunk);
}
int n;
if (isUpdate || (inLen > chunk)) {
n = engineUpdate(inArray, 0, chunk, outArray, outOfs);
} else {
n = engineDoFinal(inArray, 0, chunk, outArray, outOfs);
}
total += n;
outOfs += n;
inLen -= chunk;
} while (inLen > 0);
}
output.position(outPos + total);
} else { // output does not have an accessible byte[]
if (a1) { // but input has an accessible byte[]
inArray = input.array();
int inOfs = input.arrayOffset() + inPos;
} else { // output does not have an accessible byte[]
byte[] outArray = null;
if (isUpdate) {
outArray = engineUpdate(inArray, inOfs, inLen);
} else {
outArray = engineDoFinal(inArray, inOfs, inLen);
}
input.position(inLimit);
if (outArray != null && outArray.length != 0) {
output.put(outArray);
total = outArray.length;
}
} else { // input also does not have an accessible byte[]
inArray = new byte[getTempArraySize(inLen)];
do {
int chunk = Math.min(inLen, inArray.length);
if (chunk > 0) {
input.get(inArray, 0, chunk);
}
int n;
if (isUpdate || (inLen > chunk)) {
outArray = engineUpdate(inArray, 0, chunk);
} else {
outArray = engineDoFinal(inArray, 0, chunk);
}
if (outArray != null && outArray.length != 0) {
output.put(outArray);
total += outArray.length;
}
inLen -= chunk;
} while (inLen > 0);
// adjust input position manually
input.position(inLimit);
}
} else { // input does not have an accessible byte[]
// have to assume the worst, since we have no way of determine
// if input and output overlaps or not
byte[] tempOut = new byte[outLenNeeded];
int outOfs = 0;
byte[] tempIn = new byte[getTempArraySize(inLen)];
do {
int chunk = Math.min(inLen, tempIn.length);
if (chunk > 0) {
input.get(tempIn, 0, chunk);
}
int n;
if (isUpdate || (inLen > chunk)) {
n = engineUpdate(tempIn, 0, chunk, tempOut, outOfs);
} else {
n = engineDoFinal(tempIn, 0, chunk, tempOut, outOfs);
}
outOfs += n;
total += n;
inLen -= chunk;
} while (inLen > 0);
if (total > 0) {
output.put(tempOut, 0, total);
}
}
return total;
}

17
src/java.base/share/classes/sun/security/util/CurveDB.java
View file

@ -104,21 +104,10 @@ public class CurveDB {
if (namedCurve.getCurve().getField().getFieldSize() != fieldSize) {
continue;
}
if (namedCurve.getCurve().equals(params.getCurve()) == false) {
continue;
if (ECUtil.equals(namedCurve, params)) {
// everything matches our named curve, return it
return namedCurve;
}
if (namedCurve.getGenerator().equals(params.getGenerator()) ==
false) {
continue;
}
if (namedCurve.getOrder().equals(params.getOrder()) == false) {
continue;
}
if (namedCurve.getCofactor() != params.getCofactor()) {
continue;
}
// everything matches our named curve, return it
return namedCurve;
}
// no match found
return null;

19
src/java.base/share/classes/sun/security/util/ECUtil.java
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2006, 2018, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2006, 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
@ -32,7 +32,7 @@ import java.security.interfaces.*;
import java.security.spec.*;
import java.util.Arrays;
public class ECUtil {
public final class ECUtil {
// Used by SunPKCS11 and SunJSSE.
public static ECPoint decodePoint(byte[] data, EllipticCurve curve)
@ -220,6 +220,21 @@ public class ECUtil {
return nameSpec.getName();
}
public static boolean equals(ECParameterSpec spec1, ECParameterSpec spec2) {
if (spec1 == spec2) {
return true;
}
if (spec1 == null || spec2 == null) {
return false;
}
return (spec1.getCofactor() == spec2.getCofactor() &&
spec1.getOrder().equals(spec2.getOrder()) &&
spec1.getCurve().equals(spec2.getCurve()) &&
spec1.getGenerator().equals(spec2.getGenerator()));
}
// Convert the concatenation R and S in into their DER encoding
public static byte[] encodeSignature(byte[] signature) throws SignatureException {

47
src/java.base/share/classes/sun/security/util/SignatureUtil.java
View file

@ -28,6 +28,7 @@ package sun.security.util;
import java.io.IOException;
import java.security.*;
import java.security.spec.*;
import java.util.Locale;
import sun.security.rsa.RSAUtil;
import jdk.internal.access.SharedSecrets;
@ -74,14 +75,9 @@ public class SignatureUtil {
AlgorithmParameters params)
throws ProviderException {
sigName = checkName(sigName);
sigName = checkName(sigName).toUpperCase(Locale.ENGLISH);
AlgorithmParameterSpec paramSpec = null;
if (params != null) {
if (sigName.toUpperCase().indexOf("RSA") == -1) {
throw new ProviderException
("Unrecognized algorithm for signature parameters " +
sigName);
}
// AlgorithmParameters.getAlgorithm() may returns oid if it's
// created during DER decoding. Convert to use the standard name
// before passing it to RSAUtil
@ -93,7 +89,20 @@ public class SignatureUtil {
throw new ProviderException(e);
}
}
paramSpec = RSAUtil.getParamSpec(params);
if (sigName.indexOf("RSA") != -1) {
paramSpec = RSAUtil.getParamSpec(params);
} else if (sigName.indexOf("ECDSA") != -1) {
try {
paramSpec = params.getParameterSpec(ECParameterSpec.class);
} catch (Exception e) {
throw new ProviderException("Error handling EC parameters", e);
}
} else {
throw new ProviderException
("Unrecognized algorithm for signature parameters " +
sigName);
}
}
return paramSpec;
}
@ -103,17 +112,31 @@ public class SignatureUtil {
public static AlgorithmParameterSpec getParamSpec(String sigName,
byte[] paramBytes)
throws ProviderException {
sigName = checkName(sigName);
sigName = checkName(sigName).toUpperCase(Locale.ENGLISH);
AlgorithmParameterSpec paramSpec = null;
if (paramBytes != null) {
if (sigName.toUpperCase().indexOf("RSA") == -1) {
if (sigName.indexOf("RSA") != -1) {
AlgorithmParameters params =
createAlgorithmParameters(sigName, paramBytes);
paramSpec = RSAUtil.getParamSpec(params);
} else if (sigName.indexOf("ECDSA") != -1) {
try {
Provider p = Signature.getInstance(sigName).getProvider();
paramSpec = ECUtil.getECParameterSpec(p, paramBytes);
} catch (Exception e) {
throw new ProviderException("Error handling EC parameters", e);
}
// ECUtil discards exception and returns null, so we need to check
// the returned value
if (paramSpec == null) {
throw new ProviderException("Error handling EC parameters");
}
} else {
throw new ProviderException
("Unrecognized algorithm for signature parameters " +
sigName);
}
AlgorithmParameters params =
createAlgorithmParameters(sigName, paramBytes);
paramSpec = RSAUtil.getParamSpec(params);
}
return paramSpec;
}

236
src/java.base/share/man/java.1
View file

@ -109,7 +109,7 @@ the main class.
.SH DESCRIPTION
.PP
The \f[CB]java\f[R] command starts a Java application.
It does this by starting the Java Runtime Environment (JRE), loading the
It does this by starting the Java Virtual Machine (JVM), loading the
specified class, and calling that class\[aq]s \f[CB]main()\f[R] method.
The method must be declared \f[CB]public\f[R] and \f[CB]static\f[R], it must
not return any value, and it must accept a \f[CB]String\f[R] array as a
@ -566,7 +566,7 @@ marks (for example \f[CB]\-Dfoo="foo\ bar"\f[R]).
.RS
.RE
.TP
.B \f[CB]\-disableassertions\f[R][\f[CB]:\f[R][\f[I]packagename\f[R]]...|\f[CB]:\f[R]\f[I]classname\f[R]] or \f[CB]\-da\\[\f[R]:\f[CB]\\[*packagename*\\]...|\f[R]:`\f[I]classname\f[R]]
.B \f[CB]\-disableassertions\f[R][\f[CB]:\f[R][\f[I]packagename\f[R]]...|\f[CB]:\f[R]\f[I]classname\f[R]] or \f[CB]\-da\f[R][\f[CB]:\f[R][\f[I]packagename\f[R]]...|\f[CB]:\f[R]\f[I]classname\f[R]]
Disables assertions.
By default, assertions are disabled in all packages and classes.
With no arguments, \f[CB]\-disableassertions\f[R] (\f[CB]\-da\f[R]) disables
@ -606,7 +606,7 @@ Disables assertions in all system classes.
.RS
.RE
.TP
.B \f[CB]\-enableassertions\f[R][\f[CB]:\f[R][\f[I]packagename\f[R]]...|\f[CB]:\f[R]\f[I]classname\f[R]] or \f[CB]\-ea\\[\f[R]:\f[CB]\\[*packagename*\\]...|\f[R]:`\f[I]classname\f[R]]
.B \f[CB]\-enableassertions\f[R][\f[CB]:\f[R][\f[I]packagename\f[R]]...|\f[CB]:\f[R]\f[I]classname\f[R]] or \f[CB]\-ea\f[R][\f[CB]:\f[R][\f[I]packagename\f[R]]...|\f[CB]:\f[R]\f[I]classname\f[R]]
Enables assertions.
By default, assertions are disabled in all packages and classes.
With no arguments, \f[CB]\-enableassertions\f[R] (\f[CB]\-ea\f[R]) enables
@ -659,6 +659,7 @@ Prints the help message to the output stream.
.TP
.B \f[CB]\-javaagent:\f[R]\f[I]jarpath\f[R][\f[CB]=\f[R]\f[I]options\f[R]]
Loads the specified Java programming language agent.
See \f[CB]java.lang.instrument\f[R].
.RS
.RE
.TP
@ -718,12 +719,12 @@ Displays information about the modules in use.
.RE
.TP
.B \f[CB]\-\-version\f[R]
Prints product version to the error stream and exits.
Prints product version to the output stream and exits.
.RS
.RE
.TP
.B \f[CB]\-version\f[R]
Prints product version to the output stream and exits.
Prints product version to the error stream and exits.
.RS
.RE
.TP
@ -747,7 +748,7 @@ limitations by enabling the launcher to expand the contents of argument
files after shell expansion, but before argument processing.
Contents in the argument files are expanded because otherwise, they
would be specified on the command line until the
\f[CB]\-Xdisable\-\@files\f[R] option was encountered.
\f[CB]\-\-disable\-\@files\f[R] option was encountered.
.RS
.PP
The argument files can also contain the main class name and all options.
@ -856,7 +857,7 @@ are compiled to native code.
.TP
.B \f[CB]\-Xmn\f[R] \f[I]size\f[R]
Sets the initial and maximum size (in bytes) of the heap for the young
generation (nursery).
generation (nursery) in the generational collectors.
Append the letter \f[CB]k\f[R] or \f[CB]K\f[R] to indicate kilobytes,
\f[CB]m\f[R] or \f[CB]M\f[R] to indicate megabytes, or \f[CB]g\f[R] or
\f[CB]G\f[R] to indicate gigabytes.
@ -866,8 +867,10 @@ If the size for the young generation is too small, then a lot of minor
garbage collections are performed.
If the size is too large, then only full garbage collections are
performed, which can take a long time to complete.
It is recommended that you keep the size for the young generation
greater than 25% and less than 50% of the overall heap size.
It is recommended that you do not set the size for the young generation
for the G1 collector, and keep the size for the young generation greater
than 25% and less than 50% of the overall heap size for other
collectors.
The following examples show how to set the initial and maximum size of
young generation to 256 MB using various units:
.RS
@ -887,7 +890,7 @@ size of the heap for the young generation, you can use
.RE
.TP
.B \f[CB]\-Xms\f[R] \f[I]size\f[R]
Sets the initial size (in bytes) of the heap.
Sets the minimum and initial size (in bytes) of the heap.
This value must be a multiple of 1024 and greater than 1 MB.
Append the letter \f[CB]k\f[R] or \f[CB]K\f[R] to indicate kilobytes,
\f[CB]m\f[R] or \f[CB]M\f[R] to indicate megabytes, \f[CB]g\f[R] or \f[CB]G\f[R]
@ -904,16 +907,18 @@ MB using various units:
\f[R]
.fi
.PP
If you don\[aq]t set this option, then the initial size is set as the
sum of the sizes allocated for the old generation and the young
generation.
Instead of the \f[CB]\-Xms\f[R] option to set both the minimum and initial
size of the heap, you can use \f[CB]\-XX:MinHeapSize\f[R] to set the
minimum size and \f[CB]\-XX:InitialHeapSize\f[R] to set the initial size.
.PP
If you don\[aq]t set this option, the initial size is set as the sum of
the sizes allocated for the old generation and the young generation.
The initial size of the heap for the young generation can be set using
the \f[CB]\-Xmn\f[R] option or the \f[CB]\-XX:NewSize\f[R] option.
.RE
.TP
.B \f[CB]\-Xmx\f[R] \f[I]size\f[R]
Specifies the maximum size (in bytes) of the memory allocation pool in
bytes.
Specifies the maximum size (in bytes) of the heap.
This value must be a multiple of 1024 and greater than 2 MB.
Append the letter \f[CB]k\f[R] or \f[CB]K\f[R] to indicate kilobytes,
\f[CB]m\f[R] or \f[CB]M\f[R] to indicate megabytes, or \f[CB]g\f[R] or
@ -1205,13 +1210,6 @@ or directories.
.RS
.RE
.TP
.B \f[CB]\-\-disable\-\@files\f[R]
Can be used anywhere on the command line, including in an argument file,
to prevent further \f[CB]\@\f[R]\f[I]filename\f[R] expansion.
This option stops expanding \f[CB]\@\f[R]\-argfiles after the option.
.RS
.RE
.TP
.B \f[CB]\-\-source\f[R] \f[I]version\f[R]
Sets the version of the source in source\-file mode.
.RS
@ -1392,32 +1390,13 @@ By default this option is disabled.
.RS
.RE
.TP
.B \f[CB]\-XX:+FlightRecorder\f[R]
Enables the use of Java Flight Recorder (JFR) during the runtime of the
application.
.RS
.RS
.PP
\f[B]Note:\f[R] The \f[CB]\-XX:+FlightRecorder\f[R] option is no longer
required to use JFR.
This was a change made in JDK 8u40.
.RE
.RE
.TP
.B \f[CB]\-XX:FlightRecorderOptions=\f[R]\f[I]parameter\f[R]\f[CB]=\f[R]\f[I]value\f[R]
.B \f[CB]\-XX:FlightRecorderOptions=\f[R]\f[I]parameter\f[R]\f[CB]=\f[R]\f[I]value\f[R] (or)\f[CB]\-XX:FlightRecorderOptions:\f[R]\f[I]parameter\f[R]\f[CB]=\f[R]\f[I]value\f[R]
Sets the parameters that control the behavior of JFR.
.RS
.PP
The following list contains the available JFR
\f[I]parameter\f[R]\f[CB]=\f[R]\f[I]value\f[R] entries:
.TP
.B \f[CB]allow_threadbuffers_to_disk=\f[R]{\f[CB]true\f[R]|\f[CB]false\f[R]}
Specifies whether thread buffers are written directly to disk if the
buffer thread is blocked.
By default, this parameter is disabled.
.RS
.RE
.TP
.B \f[CB]globalbuffersize=\f[R]\f[I]size\f[R]
Specifies the total amount of primary memory used for data retention.
The default value is based on the value specified for
@ -1492,7 +1471,8 @@ performance.
.TP
.B \f[CB]threadbuffersize=\f[R]\f[I]size\f[R]
Specifies the per\-thread local buffer size (in bytes).
By default, the local buffer size is set to 8 kilobytes.
By default, the local buffer size is set to 8 kilobytes, with a minimum
value of 4 kilobytes.
Overriding this parameter could reduce performance and is not
recommended.
.RS
@ -2978,19 +2958,17 @@ Enables Java heap optimization.
This sets various parameters to be optimal for long\-running jobs with
intensive memory allocation, based on the configuration of the computer
(RAM and CPU).
By default, the option is disabled and the heap isn't optimized.
By default, the option is disabled and the heap sizes are configured
less aggressively.
.RS
.RE
.TP
.B \f[CB]\-XX:+AlwaysPreTouch\f[R]
Enables touching of every page on the Java heap during JVM
initialization.
This gets all pages into memory before entering the \f[CB]main()\f[R]
method.
The option can be used in testing to simulate a long\-running system
with all virtual memory mapped to physical memory.
By default, this option is disabled and all pages are committed as JVM
heap space fills.
Requests the VM to touch every page on the Java heap after requesting it
from the operating system and before handing memory out to the
application.
By default, this option is disabled and all pages are committed as the
application uses the heap space.
.RS
.RE
.TP
@ -3026,12 +3004,10 @@ initiating occupancy fraction.
.RS
.PP
The following example shows how to set the factor to 20%:
.IP
.nf
\f[CB]
>\ \ \ `\-XX:CMSInitiatingOccupancyFraction=20`
\f[R]
.fi
.RS
.PP
\f[CB]\-XX:CMSInitiatingOccupancyFraction=20\f[R]
.RE
.RE
.TP
.B \f[CB]\-XX:CMSIncrementalDutySafetyFactor=\f[R]\f[I]percent\f[R]
@ -3095,11 +3071,14 @@ deprecated \f[CB]\-XX:+UseConcMarkSweepGC\f[R] option and the
.RS
.RE
.TP
.B \f[CB]\-XX:+ExplicitGCInvokesConcurrentAndUnloadsClasses\f[R]
Enables invoking of concurrent GC by using the \f[CB]System.gc()\f[R]
request and unloading of classes during the concurrent GC cycle.
This option is disabled by default and can be enabled only with the
deprecated \f[CB]\-XX:+UseConcMarkSweepGC\f[R] option.
.B \f[CB]\-XX:G1AdaptiveIHOPNumInitialSamples=\f[R]\f[I]number\f[R]
When \f[CB]\-XX:UseAdaptiveIHOP\f[R] is enabled, this option sets the
number of completed marking cycles used to gather samples until G1
adaptively determines the optimum value of
\f[CB]\-XX:InitiatingHeapOccupancyPercent\f[R].
Before, G1 uses the value of
\f[CB]\-XX:InitiatingHeapOccupancyPercent\f[R] directly for this purpose.
The default value is 3.
.RS
.RE
.TP
@ -3107,10 +3086,8 @@ deprecated \f[CB]\-XX:+UseConcMarkSweepGC\f[R] option.
Sets the size of the regions into which the Java heap is subdivided when
using the garbage\-first (G1) collector.
The value is a power of 2 and can range from 1 MB to 32 MB.
The goal is to have around 2048 regions based on the minimum Java heap
size.
The default region size is determined ergonomically based on the heap
size.
size with a goal of approximately 2048 regions.
.RS
.PP
The following example sets the size of the subdivisions to 16 MB:
@ -3137,8 +3114,6 @@ The default value is 60 percent of your Java heap.
.PP
This is an experimental flag.
This setting replaces the \f[CB]\-XX:DefaultMaxNewGenPercent\f[R] setting.
.PP
This setting isn\[aq]t available in Java HotSpot VM build 23 or earlier.
.RE
.TP
.B \f[CB]\-XX:G1MixedGCCountTarget=\f[R]\f[I]number\f[R]
@ -3148,8 +3123,6 @@ cycle to collect old regions with at most
The default is 8 mixed garbage collections.
The goal for mixed collections is to be within this target number.
.RS
.PP
This setting isn\[aq]t available in Java HotSpot VM build 23 or earlier.
.RE
.TP
.B \f[CB]\-XX:G1MixedGCLiveThresholdPercent=\f[R]\f[I]percent\f[R]
@ -3161,8 +3134,6 @@ The default occupancy is 85 percent.
This is an experimental flag.
This setting replaces the
\f[CB]\-XX:G1OldCSetRegionLiveThresholdPercent\f[R] setting.
.PP
This setting isn\[aq]t available in Java HotSpot VM build 23 or earlier.
.RE
.TP
.B \f[CB]\-XX:G1NewSizePercent=\f[R]\f[I]percent\f[R]
@ -3173,8 +3144,6 @@ The default value is 5 percent of your Java heap.
.PP
This is an experimental flag.
This setting replaces the \f[CB]\-XX:DefaultMinNewGenPercent\f[R] setting.
.PP
This setting isn\[aq]t available in Java HotSpot VM build 23 or earlier.
.RE
.TP
.B \f[CB]\-XX:G1OldCSetRegionThresholdPercent=\f[R]\f[I]percent\f[R]
@ -3182,8 +3151,6 @@ Sets an upper limit on the number of old regions to be collected during
a mixed garbage collection cycle.
The default is 10 percent of the Java heap.
.RS
.PP
This setting isn\[aq]t available in Java HotSpot VM build 23 or earlier.
.RE
.TP
.B \f[CB]\-XX:G1ReservePercent=\f[R]\f[I]percent\f[R]
@ -3202,10 +3169,20 @@ The following example sets the reserved heap to 20%:
.RE
.RE
.TP
.B \f[CB]\-XX:InitialHeapOccupancyPercent=\f[R]\f[I]percent\f[R]
Sets the Java heap occupancy threshold that triggers a marking cycle.
The default occupancy is 45 percent of the entire Java heap.
.B \f[CB]\-XX:+G1UseAdaptiveIHOP\f[R]
Controls adaptive calculation of the old generation occupancy to start
background work preparing for an old generation collection.
If enabled, G1 uses \f[CB]\-XX:InitiatingHeapOccupancyPercent\f[R] for the
first few times as specified by the value of
\f[CB]\-XX:G1AdaptiveIHOPNumInitialSamples\f[R], and after that adaptively
calculates a new optimum value for the initiating occupancy
automatically.
Otherwise, the old generation collection process always starts at the
old generation occupancy determined by
\f[CB]\-XX:InitiatingHeapOccupancyPercent\f[R].
.RS
.PP
The default is enabled.
.RE
.TP
.B \f[CB]\-XX:InitialHeapSize=\f[R]\f[I]size\f[R]
@ -3276,15 +3253,18 @@ to 4:
.RE
.TP
.B \f[CB]\-XX:InitiatingHeapOccupancyPercent=\f[R]\f[I]percent\f[R]
Sets the percentage of the heap occupancy (0 to 100) at which to start a
concurrent GC cycle.
It\[aq]s used by garbage collectors that trigger a concurrent GC cycle
based on the occupancy of the entire heap, not just one of the
generations (for example, the G1 garbage collector).
Sets the percentage of the old generation occupancy (0 to 100) at which
to start the first few concurrent marking cycles for the G1 garbage
collector.
.RS
.PP
By default, the initiating value is set to 45%.
A value of 0 implies nonstop GC cycles.
A value of 0 implies nonstop concurrent GC cycles from the beginning
until G1 adaptively sets this value.
.PP
See also the \f[CB]\-XX:G1UseAdaptiveIHOP\f[R] and
\f[CB]\-XX:G1AdaptiveIHOPNumInitialSamples\f[R] options.
.PP
The following example shows how to set the initiating heap occupancy to
75%:
.RS
@ -3298,7 +3278,9 @@ Sets a target for the maximum GC pause time (in milliseconds).
This is a soft goal, and the JVM will make its best effort to achieve
it.
The specified value doesn\[aq]t adapt to your heap size.
By default, there\[aq]s no maximum pause time value.
By default, for G1 the maximum pause time target is 200 milliseconds.
The other generational collectors do not use a pause time goal by
default.
.RS
.PP
The following example shows how to set the maximum target pause time to
@ -3332,13 +3314,6 @@ allocated memory to 80 MB using various units:
\f[R]
.fi
.PP
On Oracle Solaris 7 and Oracle Solaris 8 SPARC platforms, the upper
limit for this value is approximately 4,000 MB minus overhead amounts.
On Oracle Solaris 2.6 and x86 platforms, the upper limit is
approximately 2,000 MB minus overhead amounts.
On Linux platforms, the upper limit is approximately 2,000 MB minus
overhead amounts.
.PP
The \f[CB]\-XX:MaxHeapSize\f[R] option is equivalent to \f[CB]\-Xmx\f[R].
.RE
.TP
@ -3450,6 +3425,32 @@ option to keep the Java heap small by reducing the dynamic footprint for
embedded applications.
.RE
.TP
.B \f[CB]\-XX:MinHeapSize=\f[R]\f[I]size\f[R]
Sets the minimum size (in bytes) of the memory allocation pool.
This value must be either 0, or a multiple of 1024 and greater than 1
MB.
Append the letter \f[CB]k\f[R] or \f[CB]K\f[R] to indicate kilobytes,
\f[CB]m\f[R] or \f[CB]M\f[R] to indicate megabytes, or \f[CB]g\f[R] or
\f[CB]G\f[R] to indicate gigabytes.
The default value is selected at run time based on the system
configuration.
.RS
.PP
The following examples show how to set the mimimum size of allocated
memory to 6 MB using various units:
.IP
.nf
\f[CB]
\-XX:MinHeapSize=6291456
\-XX:MinHeapSize=6144k
\-XX:MinHeapSize=6m
\f[R]
.fi
.PP
If you set this option to 0, then the minimum size is set to the same
value as the initial size.
.RE
.TP
.B \f[CB]\-XX:NewRatio=\f[R]\f[I]ratio\f[R]
Sets the ratio between young and old generation sizes.
By default, this option is set to 2.
@ -3493,23 +3494,13 @@ The \f[CB]\-XX:NewSize\f[R] option is equivalent to \f[CB]\-Xmn\f[R].
.RE
.TP
.B \f[CB]\-XX:ParallelGCThreads=\f[R]\f[I]threads\f[R]
Sets the value of the stop\-the\-world (STW) worker threads.
This option sets the value of \f[I]threads\f[R] to the number of logical
processors.
The value of \f[I]threads\f[R] is the same as the number of logical
processors up to a value of 8.
Sets the number of the stop\-the\-world (STW) worker threads.
The default value depends on the number of CPUs available to the JVM and
the garbage collector selected.
.RS
.PP
If there are more than 8 logical processors, then this option sets the
value of \f[I]threads\f[R] to approximately 5/8 of the logical
processors.
This works in most cases except for larger SPARC systems where the value
of \f[I]threads\f[R] can be approximately 5/16 of the logical processors.
.PP
The default value depends on the number of CPUs available to the JVM.
.PP
For example, to set the number of threads for parallel GC to 2, specify
the following option:
For example, to set the number of threads for G1 GC to 2, specify the
following option:
.RS
.PP
\f[CB]\-XX:ParallelGCThreads=2\f[R]
@ -3749,6 +3740,22 @@ This option is enabled by default.
To disable the use of TLABs, specify the option \f[CB]\-XX:\-UseTLAB\f[R].
.RS
.RE
.TP
.B \f[CB]\-XX:+UseZGC\f[R]
Enables the use of the Z garbage collector.
This garbage collector is best for providing lowest latency with large
Java heaps at some throughput cost.
This is an experimental garbage collector, you need to specify
\f[CB]\-XX:+UnlockExperimentalVMOptions\f[R] before \f[CB]\-XX:+UseZGC\f[R]
on the command line.
.RS
.PP
Example:
.RS
.PP
\f[CB]\-XX:+UnlockExperimentalVMOptions\ \-XX:+UseZGC\f[R]
.RE
.RE
.SH DEPRECATED JAVA OPTIONS
.PP
These \f[CB]java\f[R] options are deprecated and might be removed in a
@ -3788,6 +3795,13 @@ You can enable it only for classes with older versions of the bytecode.
.RS
.RE
.TP
.B \f[CB]\-XX:+FlightRecorder\f[R]
Enables the use of Java Flight Recorder (JFR) during the runtime of the
application.
Since JDK 8u40 this option has not been required to use JFR.
.RS
.RE
.TP
.B \f[CB]\-XX:+TraceClassLoading\f[R]
Enables tracing of classes as they are loaded.
By default, this option is disabled and classes aren\[aq]t traced.
@ -3926,8 +3940,8 @@ sign (\f[CB]\@\f[R]), it expands the contents of that file into an
argument list just as they would be specified on the command line.
.PP
The \f[CB]java\f[R] launcher expands the argument file contents until it
encounters the \f[CB]\-Xdisable\-\@files\f[R] option.
You can use the \f[CB]\-Xdisable\-\@files\f[R] option anywhere on the
encounters the \f[CB]\-\-disable\-\@files\f[R] option.
You can use the \f[CB]\-\-disable\-\@files\f[R] option anywhere on the
command line, including in an argument file, to stop \f[CB]\@\f[R]
argument files expansion.
.PP
@ -5603,7 +5617,7 @@ Use the following commands and advanced options to achieve lower
response times for your application:
.RS
.PP
\f[CB]java\ \-XX:+UseG1GC\ \-Xms26g\ Xmx26g\ \-XX:MaxGCPauseMillis=500\f[R]
\f[CB]java\ \-XX:+UseG1GC\ \-XX:MaxGCPauseMillis=100\f[R]
.RE
.SS Keeping the Java Heap Small and Reducing the Dynamic Footprint of
Embedded Applications