Java JVM选项解释列表(转)
A Collection of JVM Options
compiled by: Joseph D. Mocker (Sun Microsystems, Inc.)
revision: 28.Aug.2007
References:
compiled by: Joseph D. Mocker (Sun Microsystems, Inc.)
revision: 28.Aug.2007
This document is a compilation of all the JVM options for various versions of the JVM on primarily SPARC/Solaris Platform. The descriptions for each option are taken mostly verbatim from the reference documents.
The JavaTM HotSpot VM Options page makes some good points regarding the different types of options, which should be followed when reading this document as well. To paraphrase:
- Standard options recognized by the Java HotSpot VM are described on the Java Application Launcher reference pages.
- Options that begin with -X are non-standard (not guaranteed to be supported on all VM implementations), and are subject to change without notice in subsequent releases of the Java 2 SDK.
- Because the -XX options have specific system requirements for correct operation and may require privileged access to system configuration parameters, they are not recommended for casual use. These options are also subject to change without notice.
Please submit any comments, corrections, additions to jvm-options-list@sun.com .
Caveats: I am not associated with any Java Platform development group, I simply put this list together from the various reference sources I could find and without referring to any source code. I have done my best to ensure the options are valid for representative JVMs, however I have not tested every version of every JVM so it is quite possible that options may not be valid in all cases.
| Option | Type | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Description |
|---|---|---|---|---|---|---|---|---|
| -client | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Use Client HotSpot VM. Must be first option. |
| -server | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Use Server HotSpot VM. Must be first option. |
| -verbose[:class|gc|jni] | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | enable output of various pieces of the VM. specifying options twice may produce more detailed output. |
| -cp | path | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | set search path for application classes and resources |
| -classpath | path | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | set search path for application classes and resources |
| -version | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | print product version and exit |
| -showversion | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | print product version and continue |
| -fullversion | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | print full java version and exit |
| -agentlib:<libname>[=<options>] | nv | 1.6.0 | load native agent library <libname>, e.g. -agentlib:hprof see also, -agentlib:jdwp=help and -agentlib:hprof=help | |||||
| -agentpath:<pathname>[=<options>] | nv | 1.6.0 | load native agent library by full pathname | |||||
| -javaagent:<jarpath>[=<options>] | nv | 1.6.0 | load Java programming language agent, see java.lang.instrument | |||||
| -d32 | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | use a 32-bit data model if available | |
| -d64 | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | use a 64-bit data model if available | |
| -ea[:packagename...|:classname] | list | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | enable assertions | |
| -enableassertions[:packagename...|:classname] | list | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | enable assertions | |
| -da[:packagename...|:classname] | list | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | disable assertions | |
| -disableassertions[:packagename...|:classname] | list | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | disable assertions | |
| -esa | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | enable system assertions | |
| -enablesystemassertions | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | enable system assertions | |
| -dsa | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | disable system assertions | |
| -disablesystemassertions | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | disable system assertions | |
| -Dname=value | nv | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | set a system property |
| -jre-restrict-search | bool | 1.5.0 | 1.6.0 | include user private JREs in the version search | ||||
| -jre-no-restrict-search | bool | 1.5.0 | 1.6.0 | exclude user private JREs in the version search | ||||
| -Xt | bool | O | O | O | O | O | O | turn on instruction tracing |
| -Xtm | bool | O | O | O | O | O | O | turn on method tracing |
| -Xbootclasspath[/a|/p]:<path> | list | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | set, append to, or prepend to boot class path |
| -Xdebug | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | enable remote debugging |
| -Xfuture | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | enable strictest checks, anticipating future default |
| -Xcheck:jni | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | perform additional checks for JNI functions |
| -Xshare:off | bool | 1.6.0 | do not attempt to use shared class data | |||||
| -Xshare:auto | bool | 1.6.0 | use shared class data if possible (default) | |||||
| -Xshare:on | bool | 1.6.0 | require using shared class data, otherwise fail. | |||||
| -Xnoclassgc | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | disable class garbage collection |
| -Xss<size> | size | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | set maximum native stack size for any thread |
| -Xoss<size> | size | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | set maximum Java stack size for any thread. Note: This option is useless with HotSpot as HotSpot doesn't have separate native and Java stacks. |
| -Xms<size> | size | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | set initial Java heap size |
| -Xmx<size> | size | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | set maximum Java heap size |
| -Xmn<size> | size | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Size of young generation | |
| -Xrs | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | reduce the use of OS signals |
| -Xrunhprof[:help]|[:option=value, ...] | list | 1.3.1 | 1.4.0 | 1.4.2 | 1.5.0 | 1.6.0 | perform heap or cpu profiling | |
| -Xmaxjitcodesize<size> | size | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | set the maximum size (in bytes) for the JIT code area |
| -Xsqnopause | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | do not pause for user interaction on SIGQUIT |
| -Xoptimize | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Use optimizing JIT compiler (SPARC only). Replaced by -server in later VMs |
| -Xmixed | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | mixed mode execution (default) |
| -Xint | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | interpreted mode execution only |
| -Xincgc | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Incremental GC |
| -Xconcgc | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Concurrent GC. Replaced by -XX:+UseConcMarkSweepGC (available beginning with J2SE 1.4.1) | ||
| -Xprof | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Precursor to -Xrunprof. |
| -Xaprof | path | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Simple allocation profiler. unstable. debug only. |
| -Xloggc:<file> | path | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Log garbage collection actions to a specified file. | |
| -Xcomp | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Forces HotSpot to compile 100% of the code with maximum optimization. |
| -Xbatch | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Forces HotSpot to compile methods in the foreground. Normally method compilation is moved from the foreground to a background process if they take long. This allows allows the interpreted version to continue to run until the compiled version is complete. This option prevents background compiling. |
| -Xconcurrentio | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | The main feature turned on with -Xconcurrentio is to use LWP based synchronization instead of thread based synchronization. We have found certain applications to speed up by over 40%. In 1.4, LWP based synchronization is the default, but -Xconcurrentio can still help since it turns on some other internal options. |
| -Xgenconfig | bool | 1.6.0 | 1.2 option only | |||||
| -Xverifyheap | bool | O | O | O | O | O | Verify heap integrity. Replaced by -XX:+VerifyBeforeGC -XX:+VerifyAfterGC -XX:+VerifyTLE (-XX:+VerifyTLAB in J2SE 1.4) -XX:+VerifyBeforeScavenge -XX:+VerifyAfterScavenge (all debug only) | |
| -XX:AdaptivePermSizeWeight=<value> | uintx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:AdaptiveSizeDecrementScaleFactor=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:AdaptiveSizePolicyCollectionCostMargin=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:AdaptiveSizePolicyFootprintThreshold=<value> | uintx | 1.5.0 | ||||||
| -XX:AdaptiveSizePolicyInitializingSteps=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:AdaptiveSizePolicyWeight=<value> | uintx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:AdaptiveSizeThroughPutPolicy=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:AdaptiveTimeWeight=<value> | uintx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:+AdjustConcurrency | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+AggressiveHeap | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | This option instructs the JVM to push memory use to the limit: the overall heap is more than 3850MB, the allocation area of each thread is 256K, the memory management policy defers collection as long as possible, and (beginning with J2SE 1.3.1_02) some GC activity is done in parallel. |
| -XX:+AggressiveOpts | bool | 1.6.0 | ||||||
| -XX:AliasLevel=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:AllocatePrefetchDistance=<value> | intx | 1.6.0 | ||||||
| -XX:AllocatePrefetchInstr=<value> | intx | 1.6.0 | ||||||
| -XX:AllocatePrefetchLines=<value> | intx | 1.6.0 | ||||||
| -XX:AllocatePrefetchStepSize=<value> | intx | 1.6.0 | ||||||
| -XX:AllocatePrefetchStyle=<value> | intx | 1.6.0 | ||||||
| -XX:+AllowJNIEnvProxy | bool | 1.6.0 | ||||||
| -XX:+AllowUserSignalHandlers | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Do not complain if the application installs signal handlers (Solaris Only) |
| -XX:AltStackSize=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | Alternate signal stack size (in Kbytes, Solaris Only) | ||
| -XX:+AlwaysActAsServerClassMachine | bool | 1.6.0 | ||||||
| -XX:+AlwaysCompileLoopMethods | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:AlwaysInflate=<value> | intx | 1.6.0 | ||||||
| -XX:+AlwaysPreTouch | bool | 1.6.0 | ||||||
| -XX:+AlwaysTenure | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:AppendRatio=<value> | intx | 1.5.0 | 1.6.0 | |||||
| -XX:+BackgroundCompilation | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Enables or disables JIT compilation in the background. When enabled, interpreted methods are still executed until background compilation is complete. |
| -XX:BaseFootPrintEstimate=<value> | uintx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:BCEATraceLevel=<value> | intx | 1.6.0 | ||||||
| -XX:BiasedLockingBulkRebiasThreshold=<value> | intx | 1.6.0 | ||||||
| -XX:BiasedLockingBulkRevokeThreshold=<value> | intx | 1.6.0 | ||||||
| -XX:BiasedLockingDecayTime=<value> | intx | 1.6.0 | ||||||
| -XX:BiasedLockingStartupDelay=<value> | intx | 1.6.0 | ||||||
| -XX:+BindCMSThreadToCPU | bool | 1.6.0 | ||||||
| -XX:+BindGCTaskThreadsToCPUs | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:+BindScavengeThreads | bool | 1.3.1 | ||||||
| -XX:+BlockOffsetArrayUseUnallocatedBlock | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:+BytecodeVerificationLocal | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+BytecodeVerificationRemote | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+CheckJNICalls | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+CheckUnsafeOps | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | |||
| -XX:CICompilerCount=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+CICompilerCountPerCPU | bool | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:+CIDynamicCompilePriority | bool | 1.3.1 | 1.4.0 | 1.4.1 | ||||
| -XX:+CIMaxPriority | bool | 1.4.0 | 1.4.1 | |||||
| -XX:+CITime | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Time spent in JIT Compiler | |
| -XX:+ClassUnloading | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:ClearFPUAtPark=<value> | intx | 1.6.0 | ||||||
| -XX:+ClipInlining | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:CMSAbortablePrecleanMinWorkPerIteration=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:CMSAbortablePrecleanWaitMillis=<value> | intx | 1.5.0 | 1.6.0 | |||||
| -XX:+CMSAbortSemantics | bool | 1.6.0 | ||||||
| -XX:CMSBitMapYieldQuantum=<value> | uintx | 1.4.2 | 1.5.0 | |||||
| -XX:CMSBootstrapOccupancy=<value> | intx | 1.5.0 | 1.6.0 | |||||
| -XX:+CMSClassUnloadingEnabled | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | It has been reported that for 1.5, this apparently needs to be combined with -XX:+CMSPermGenSweepingEnabled in order to take effect. | ||
| -XX:+CMSCompactWhenClearAllSoftRefs | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:+CMSConcurrentMTEnabled | bool | 1.6.0 | ||||||
| -XX:CMSDictionaryChoice=<value> | intx | 1.4.0 | ||||||
| -XX:CMSExpAvgFactor=<value> | uintx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:CMSFullGCsBeforeCompaction=<value> | uintx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Parameter that affects compaction of the old generation. If at least this number of concurrent collections has not succeeded between full collection, do a compaction on full collections. If 0, always do compactions on full collections when UseCMSCompactAtFullCollection is true | ||
| -XX:CMSIncrementalDutyCycle=<value> | uintx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:CMSIncrementalDutyCycleMin=<value> | uintx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:+CMSIncrementalMode | bool | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:CMSIncrementalOffset=<value> | uintx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:+CMSIncrementalPacing | bool | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:CMSIncrementalSafetyFactor=<value> | uintx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:CMSIndexedFreeListReplenish=<value> | uintx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:CMSInitiatingOccupancyFraction=<value> | intx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Sets the threshold percentage of the used heap in the old generation at which the CMS collection takes place. For example, if set to 60, the CMS collector will be initiated every time the old generation becomes 60% full. By default, this threshold is calculated at run time, and the CMS collector might be triggered only when the old generation heap is about 80-90% full. Tuning this value can improve performance in many cases. Since the CMS collector does not suspend the mutators as it sweeps and frees memory, setting this switch can ensure that enough free memory is available for object promotion from the young generation as more data is allocated by the application. Sometimes, if this switch is not tuned, CMS collection might not be able to keep up and may fail, eventually triggering the default stop-the-world mark-compact collector. Available from J2SE1.4.1. | ||
| -XX:+CMSLoopWarn | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:CMSMarkStackSize=<value> | uintx | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:CMSMarkStackSizeMax=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:CMSMaxAbortablePrecleanLoops=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:CMSMaxAbortablePrecleanTime=<value> | intx | 1.5.0 | 1.6.0 | |||||
| -XX:+CMSNoWarning | bool | 1.4.0 | 1.4.1 | |||||
| -XX:+CMSParallelRemarkEnabled | bool | 1.4.2 | 1.5.0 | 1.6.0 | Attempt to descrease remark pauses when used with -XX:+UseParNewGC. | |||
| -XX:+CMSParallelSurvivorRemarkEnabled | bool | 1.6.0 | ||||||
| -XX:+CMSPermGenPrecleaningEnabled | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:+CMSPermGenSweepingEnabled | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | It has been reported that for 1.5, this apparently needs to be combined with -XX:+CMSClassUnloadingEnabled in order to take effect. | ||
| -XX:+CMSPLABRecordAlways | bool | 1.6.0 | ||||||
| -XX:CMSPrecleanDenominator=<value> | uintx | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:+CMSPrecleaningEnabled | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:CMSPrecleanIter=<value> | uintx | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:CMSPrecleanNumerator=<value> | uintx | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:+CMSPrecleanRefLists1 | bool | 1.5.0 | 1.6.0 | |||||
| -XX:+CMSPrecleanRefLists2 | bool | 1.5.0 | 1.6.0 | |||||
| -XX:+CMSPrecleanSurvivors1 | bool | 1.6.0 | ||||||
| -XX:+CMSPrecleanSurvivors2 | bool | 1.6.0 | ||||||
| -XX:CMSPrecleanThreshold=<value> | uintx | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:CMSRescanMultiple=<value> | uintx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:CMSRevisitStackSize=<value> | uintx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:CMSSamplingGrain=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:+CMSScavengeBeforeRemark | bool | 1.6.0 | ||||||
| -XX:CMSScheduleRemarkEdenPenetration=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:CMSScheduleRemarkEdenSizeThreshold=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:CMSScheduleRemarkSamplingRatio=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:CMSTriggerRatio=<value> | intx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:+CMSUseOldDefaults | bool | 1.6.0 | ||||||
| -XX:CMSWaitDuration=<value> | intx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:CMSWorkQueueDrainThreshold=<value> | uintx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:+CMSYield | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:CMSYieldQuantum=<value> | intx | 1.4.0 | 1.4.1 | |||||
| -XX:CMSYoungGenPerWorker=<value> | intx | 1.6.0 | ||||||
| -XX:CodeCacheExpansionSize=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:CodeCacheMinimumFreeSpace=<value> | uintx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+CodeForP6 | bool | 1.3.1 | ||||||
| -XX:+CollectGen0First | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:+CompactFields | bool | 1.6.0 | ||||||
| -XX:CompilationPolicyChoice=<value> | intx | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:CompilationRepeat=<value> | intx | 1.4.2 | 1.5.0 | |||||
| -XX:CompileCommand=<value> | ccstr | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:CompileCommandFile=<value> | ccstr | 1.4.2 | 1.5.0 | 1.6.0 | Allows you to specify alternate compiler command files. When used, this overrides the default behavior of the VM and the VM will NOT scan either the libjvm.sl directory or the current directory for a .hotspot_compiler file. | |||
| -XX:CompileOnly=<value> | ccstr | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:+CompilerThreadHintNoPreempt | bool | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:CompilerThreadPriority=<value> | intx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:CompilerThreadStackSize=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:CompileThreshold=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | number of method invocations/branches before (re-)compiling [10,000 -server, 1,500 -client] |
| -XX:+ConvertSleepToYield | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+ConvertYieldToSleep | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+DebugNonSafepoints | bool | 1.6.0 | ||||||
| -XX:DefaultInitialRAMFraction=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:DefaultMaxRAM=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:DefaultMaxRAMFraction=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:DefaultThreadPriority=<value> | intx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:DefaultTickInterval=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | O | |
| -XX:+DefaultUseSpecLock | bool | 1.3.1 | 1.4.0 | |||||
| -XX:DeferPollingPageLoopCount=<value> | intx | 1.6.0 | ||||||
| -XX:DeferThrSuspendLoopCount=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:DelayTickAdjustment=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | O | |
| -XX:+DisableAttachMechanism | bool | 1.6.0 | ||||||
| -XX:+DisableExplicitGC | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Disable calls to System.gc(), JVM still performs garbage collection when necessary |
| -XX:+DisplayVMOutput | bool | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:+DisplayVMOutputToStderr | bool | 1.5.0 | 1.6.0 | |||||
| -XX:+DisplayVMOutputToStdout | bool | 1.5.0 | 1.6.0 | |||||
| -XX:+DontCompileHugeMethods | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+DontYieldALot | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+DontYieldALotInterval | bool | Interval in milliseconds between yields. (debug only) | ||||||
| -XX:+DTraceAllocProbes | bool | 1.6.0 | ||||||
| -XX:+DTraceMethodProbes | bool | 1.6.0 | ||||||
| -XX:+DTraceMonitorProbes | bool | 1.6.0 | ||||||
| -XX:+DumpSharedSpaces | bool | 1.5.0 | 1.6.0 | |||||
| -XX:+EagerInitialization | bool | 1.4.1 | ||||||
| -XX:+EagerXrunInit | bool | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:EmitLFence=<value> | intx | 1.6.0 | ||||||
| -XX:EmitSync=<value> | intx | 1.6.0 | ||||||
| -XX:+EnableJVMPIInstructionStartEvent | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Enables or disables the JVMPI event, JVMPI_EVENT_INSTRUCTION_START, which is sent when each instruction is issued by the interpreter |
| -XX:ErrorFile=<value> | ccstr | 1.6.0 | ||||||
| -XX:+EstimateArgEscape | bool | 1.6.0 | ||||||
| -XX:EventLogLength=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+ExitOnBadLibThread | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | ||
| -XX:+ExplicitGCInvokesConcurrent | bool | 1.6.0 | ||||||
| -XX:+ExtendedDTraceProbes | bool | 1.6.0 | ||||||
| -XX:+FailOverToOldVerifier | bool | 1.6.0 | ||||||
| -XX:+FasterSync | bool | 1.3.1 | ||||||
| -XX:+FastNMethodDependencies | bool | 1.4.1 | 1.4.2 | 1.5.0 | ||||
| -XX:+FastTLABRefill | bool | 1.5.0 | ||||||
| -XX:FieldsAllocationStyle=<value> | intx | 1.6.0 | ||||||
| -XX:+FilterSpuriousWakeups | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:FloatCacheThreshold=<value> | intx | 1.4.0 | ||||||
| -XX:+FLSVerifyAllHeapReferences | bool | 1.6.0 | ||||||
| -XX:+FLSVerifyIndexTable | bool | 1.6.0 | ||||||
| -XX:+FLSVerifyLists | bool | 1.6.0 | ||||||
| -XX:+ForceSharedSpaces | bool | 1.5.0 | 1.6.0 | |||||
| -XX:+ForceTimeHighResolution | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+ForceUseSpecLock | bool | 1.3.1 | 1.4.0 | |||||
| -XX:FreqInlineSize=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Integer specifying maximum number of bytecode instructions in a frequently executed method which gets inlined. |
| -XX:+FullSpeedJVMDI | bool | 1.4.0 | 1.4.1 | 1.4.2 | ||||
| -XX:GCHeapFreeLimit=<value> | uintx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Used with -XX:+UseParallelGC to help prevent out-of-memory exceptions from occuring during garbage collection. This parameter specifies the lower limit on the amount of space freed during a garbage collection in per cent of the maximum heap (default is 5). | ||
| -XX:GCTaskTimeStampEntries=<value> | uintx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:GCTimeLimit=<value> | uintx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Used with -XX:+UseParallelGC to help prevent out-of-memory exceptions from occuring during garbage collection. This parameter specifies the upper limit on the amount of time spent in garbage collection in per cent of total time (default is 90) | ||
| -XX:GCTimeRatio=<value> | uintx | 1.5.0 | 1.6.0 | The ratio of GC time to application time, ratio being: 1 / (1 + nnn). For example -XX:GCTimeRatio=19 sets a goal of 5% of the total time for GC. | ||||
| -XX:+HandlePromotionFailure | bool | 1.5.0 | 1.6.0 | |||||
| -XX:hashCode=<value> | intx | 1.6.0 | ||||||
| -XX:+HeapDumpOnOutOfMemoryError | bool | 1.6.0 | ||||||
| -XX:HeapDumpPath=<value> | ccstr | 1.6.0 | ||||||
| -XX:HPILibPath=<value> | ccstr | 1.6.0 | ||||||
| -XX:InitialCodeCacheSize=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:InitialSurvivorRatio=<value> | uintx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:InitialTenuringThreshold=<value> | intx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:+Inline | bool | 1.3.1 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:InlineSmallCode=<value> | intx | 1.3.1 | 1.4.2 | |||||
| -XX:+InlineUnreachedCalls | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | ||
| -XX:+InstallMethods | bool | 1.3.1 | ||||||
| -XX:InterpreterProfilePercentage=<value> | intx | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:+JavaMonitorsInStackTrace | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Useful to display more stack trace information about monitors |
| -XX:JavaPriority1_To_OSPriority=<value> | intx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:JavaPriority10_To_OSPriority=<value> | intx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:JavaPriority2_To_OSPriority=<value> | intx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:JavaPriority3_To_OSPriority=<value> | intx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:JavaPriority4_To_OSPriority=<value> | intx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:JavaPriority5_To_OSPriority=<value> | intx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:JavaPriority6_To_OSPriority=<value> | intx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:JavaPriority7_To_OSPriority=<value> | intx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:JavaPriority8_To_OSPriority=<value> | intx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:JavaPriority9_To_OSPriority=<value> | intx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:+JNIDetachReleasesMonitors | bool | 1.6.0 | ||||||
| -XX:+JVMPICheckGCCompatibility | bool | 1.5.0 | 1.6.0 | |||||
| -XX:LargePageHeapSizeThreshold=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:LargePageSizeInBytes=<value> | uintx | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:+LazyBootClassLoader | bool | 1.6.0 | ||||||
| -XX:+LIRCacheLocals | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | |||
| -XX:+LIRFillDelaySlots | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | |||
| -XX:+LIROptimize | bool | 1.4.0 | ||||||
| -XX:+LIROptimizeDeleteOps | bool | 1.4.0 | ||||||
| -XX:+LIROptimizeFloats | bool | 1.4.0 | ||||||
| -XX:+LIROptimizeStack | bool | 1.4.0 | ||||||
| -XX:LocalCacheThreshold=<value> | intx | 1.4.0 | ||||||
| -XX:+LogCompilation | bool | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:LogFile=<value> | ccstr | 1.4.2 | 1.5.0 | |||||
| -XX:+LogVMOutput | bool | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:MallocVerifyInterval=<value> | intx | 1.6.0 | ||||||
| -XX:MallocVerifyStart=<value> | intx | 1.6.0 | ||||||
| -XX:+ManagementServer | bool | 1.5.0 | 1.6.0 | |||||
| -XX:MarkSweepAlwaysCompactCount=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:MarkSweepDeadRatio=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:MaxBCEAEstimateLevel=<value> | intx | 1.6.0 | ||||||
| -XX:MaxBCEAEstimateSize=<value> | intx | 1.6.0 | ||||||
| -XX:MaxDirectMemorySize=<value> | intx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:+MaxFDLimit | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Bump the number of file descriptors to max. (Solaris only) |
| -XX:MaxGCMinorPauseMillis=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:MaxGCPauseMillis=<value> | uintx | 1.5.0 | 1.6.0 | A hint to the virtual machine that pause times of nnn milliseconds or less are desired. The vm will adjust the java heap size and other gc-related parameters in an attempt to keep gc-induced pauses shorter than nnn milliseconds. Note that this may cause the vm to reduce overall throughput, and in some cases the vm will not be able to meet the desired pause time goal. | ||||
| -XX:MaxHeapFreeRatio=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | heap free percentage (default 70) |
| -XX:MaxHeapSize=<value> | uintx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:MaxInlineLevel=<value> | intx | 1.3.1 | 1.4.2 | |||||
| -XX:MaxInlineSize=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Integer specifying maximum number of bytecode instructions in a method which gets inlined. |
| -XX:MaxJavaStackTraceDepth=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:MaxLiveObjectEvacuationRatio=<value> | uintx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:MaxNewSize=<value> | uintx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Maximum size of new generation (in bytes) [32m sparc, 2.5m intel for 1.3, no limit for 1.4 as NewRatio is now used to determine MaxNewSize] |
| -XX:MaxPermHeapExpansion=<value> | uintx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:MaxPermSize=<value> | uintx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Size of the Permanent Generation |
|
||||||||
| -XX:MaxRecursiveInlineLevel=<value> | intx | 1.3.1 | 1.4.2 | |||||
| -XX:MaxSurvivorShrinkRatio=<value> | size_t | 1.3.1 | ||||||
| -XX:MaxTenuringThreshold=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | This switch determines how much the objects may age in the young generation before getting promoted to the older generation. The default value is 31. For a big enough young generation and "survivor space", the long-lived objects may be copied up to 31 times between the survivor spaces before they are finally promoted to the old generation. |
| -XX:MaxTickInterval=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | O | |
| -XX:MaxTLABRatio=<value> | uintx | 1.4.0 | 1.4.1 | 1.4.2 | ||||
| -XX:MaxTLERatio=<value> | 1.3.1 | 1.6.0 | ||||||
| -XX:MinHeapDeltaBytes=<value> | uintx | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:MinHeapFreeRatio=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | heap free percentage (default 40) |
| -XX:MinOldHeapExpansion=<value> | size_t | 1.3.1 | ||||||
| -XX:MinPermHeapExpansion=<value> | uintx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:MinSurvivorRatio=<value> | uintx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:MinTickInterval=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | O | |
| -XX:MinTLABSize=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:NativeSynchronization=<value> | ccstr | 1.5.0 | ||||||
| -XX:+NeverActAsServerClassMachine | bool | 1.6.0 | ||||||
| -XX:+NeverTenure | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:NewRatio=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Ratio of new/old generation sizes [sparc -server: 2, sparc -client: 4 (1.3) 8 (1.3.1+), intel: 12] |
| -XX:NewSize=<value> | uintx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Default size of new generation (in bytes) [sparc 2.125M, intel: 640k] |
|
||||||||
| -XX:NewSizeThreadIncrease=<value> | uintx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | As more threads are created in a server application, the object allocation rate may increase with the number of active threads. The number of active threads is considered when adjusting the size of the young space, after a garbage collection. This flag specifies, in Kilobytes, the increment in young object space size, per active thread, to accomodate potentially faster object allocation rate. |
| -XX:NmethodSweepFraction=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:NMethodSweepInterval=<value> | 1.3.1 | |||||||
| -XX:NUMAChunkResizeWeight=<value> | intx | 1.6.0 | ||||||
| -XX:NUMAPageScanRate=<value> | intx | 1.6.0 | ||||||
| -XX:NUMASpaceResizeRate=<value> | intx | 1.6.0 | ||||||
| -XX:+NUMAStats | bool | 1.6.0 | ||||||
| -XX:OldPLABSize=<value> | uintx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:OldSize=<value> | uintx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+OmitStackTraceInFastThrow | bool | 1.6.0 | ||||||
| -XX:OnError=<value> | ccstr | 1.5.0 | 1.6.0 | The Hotspot JVM includes a fatal error hander that can run a user-supplied script or program if the JVM aborts. A debug tool can also connect to a hung JVM or core file using the Hotspot JVM serviceability agent connector. | ||||
| -XX:OnOutOfMemoryError=<value> | ccstr | 1.6.0 | ||||||
| -XX:OnStackReplacePercentage=<value> | intx | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:OnStackReplaceThreshold=<value> | 1.3.1 | |||||||
| -XX:+OptimizeSinglePrecision | bool | 1.4.0 | ||||||
| -XX:+OverrideDefaultLibthread | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | On Solaris 9, this option is not necessary. On Solaris 8, J2SE? versions 1.3.1_02+ and 1.4+ require this option when using the alternate threads library. This option is not possible on pre-Solaris 8 operating environments. | |
| -XX:OversizedCarThreshold=<value> | uintx | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | O | ||
| -XX:ParallelGCBufferWastePct=<value> | intx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:ParallelGCG1AllocBufferSize=<value> | intx | 1.4.1 | 1.4.2 | 1.5.0 | ||||
| -XX:ParallelGCOldGenAllocBufferSize=<value> | intx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Java 6: se -XX:OldPLABSize in place of -XX:ParallelGCOldGenAllocBufferSize in the future. | ||
| -XX:+ParallelGCRetainPLAB | bool | 1.5.0 | 1.6.0 | |||||
| -XX:ParallelGCTermSpinLoopMS=<value> | intx | 1.4.1 | 1.4.2 | 1.5.0 | ||||
| -XX:ParallelGCThreads=<value> | uintx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | This switch sets the number of parallel GC threads that the JVM must run for performing garbage collection in the young generation. The default value of n is equal to the number of CPUs on the system. However, it has been observed that tweaking this number may improve performance in some cases. An example might be that of multiple instances of JVM running on a single multi-CPU system. In this case, the number of parallel GC threads for each JVM may need to be set to less than the number of CPUs by using this switch. Available from J2SE1.4.1. | ||
|
||||||||
| -XX:ParallelGCToSpaceAllocBufferSize=<value> | intx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Java 6: Use -XX:YoungPLABSize in place of -XX:ParallelGCToSpaceAllocBufferSize in the future. | ||
| -XX:+ParallelGCVerbose | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:+ParallelRefProcEnabled | bool | 1.5.0 | 1.6.0 | |||||
| -XX:ParCMSPromoteBlocksToClaim=<value> | intx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Java 6: Use -XX:CMSParPromoteBlocksToClaim in place of -XX:ParCMSPromoteBlocksToClaim in the future. | ||
| -XX:ParGCArrayScanChunk=<value> | intx | 1.5.0 | 1.6.0 | |||||
| -XX:ParGCDesiredObjsFromOverflowList=<value> | intx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:ParGCMaxArrayAsNormalObject=<value> | intx | 1.4.1 | 1.4.2 | |||||
| -XX:+ParkTLE | bool | 1.3.1 | ||||||
| -XX:+PassParametersInRegisters | bool | 1.3.1 | ||||||
| -XX:+PauseAtStartup | bool | 1.6.0 | ||||||
| -XX:PauseAtStartupFile=<value> | ccstr | 1.6.0 | ||||||
| -XX:PerBytecodeRecompilationCutoff=<value> | intx | 1.6.0 | ||||||
| -XX:PerBytecodeTrapLimit=<value> | intx | 1.6.0 | ||||||
| -XX:+PerfAllowAtExitRegistration | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:+PerfBypassFileSystemCheck | bool | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:PerfDataMemorySize=<value> | intx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:PerfDataSamplingInterval=<value> | intx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:+PerfDataSaveToFile | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
|
|
||||||||
| -XX:+PerfDisableSharedMem | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:PerfMaxStringConstLength=<value> | intx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:PerMethodRecompilationCutoff=<value> | intx | 1.6.0 | ||||||
| -XX:PerMethodTrapLimit=<value> | intx | 1.6.0 | ||||||
| -XX:PermGenPadding=<value> | uintx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:PermMarkSweepDeadRatio=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:PermSize=<value> | uintx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Initial size of permanent generation |
| -XX:+PostSpinYield | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:PreBlockSpin=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+PreferInterpreterNativeStubs | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:PrefetchCopyIntervalInBytes=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Prefetch n bytes ahead for scavenge copy destination area. The default is 0. The ideal value may vary depending on the processor. |
| -XX:PrefetchFieldsAhead=<value> | intx | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:PrefetchScanIntervalInBytes=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Prefetch n bytes ahead for scavenge scan area. The default is 0. The ideal value may vary depending on the processor. |
| -XX:PrefetchScavengeFieldsAhead=<value> | 1.3.1 | Prefetch the next n fields of objects during scavenge. The default is 0. The ideal value may vary depending on the processor. | ||||||
| -XX:PreInflateSpin=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+PreserveAllAnnotations | bool | 1.5.0 | 1.6.0 | |||||
| -XX:PreserveMarkStackSize=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:+PreSpinYield | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:PretenureSizeThreshold=<value> | uintx | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Objects size greater than this is directly allocated in the older generation | |
| -XX:+PrintAdaptiveSizePolicy | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Prints information about adaptive size policy | ||
| -XX:+PrintClassHistogram | bool | 1.4.2 | 1.5.0 | 1.6.0 | Prints the all the java heap objects, their instance count and total space they occupy in the heap. The only downside is that you need to issue a SIGQUIT (see -Xsqnopause) which will leave the app running but will dump all of this data to stdout. Very useful to assist in identifying memory problems for example on a production platform where an CPU intensive profiler cannot be used. | |||
| -XX:+PrintCMSInitiationStatistics | bool | 1.6.0 | ||||||
| -XX:PrintCMSStatistics=<value> | intx | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | If > 0, Print statistics about the concurrent collections. For example, the number of times the concurrent collection yield to a young generation collection and the number of cards precleaned | |
| -XX:+PrintCommandLineFlags | bool | 1.5.0 | 1.6.0 | |||||
| -XX:+PrintCompilation | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | traces methods as compiled |
| -XX:+PrintConcurrentLocks | bool | 1.6.0 | ||||||
| -XX:PrintFLSCensus=<value> | intx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | if > 0, print the populations of the CMS free lists | ||
| -XX:PrintFLSStatistics=<value> | intx | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | If > 0, print statistics about the concurrent free lists. For example, a fragmentation parameter | |
| -XX:+PrintGC | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+PrintGCApplicationConcurrentTime | bool | 1.4.2 | 1.5.0 | 1.6.0 | Measure the amount of time the applications runs between collection pauses | |||
| -XX:+PrintGCApplicationStoppedTime | bool | 1.4.2 | 1.5.0 | 1.6.0 | Measure the length of the collection pauses. | |||
| -XX:+PrintGCDetails | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Gives some details about the GCs, such as size of the young and old generation before and after GCs, size of total heap, time it takes for a GC to happen in young and old generation, size of objects promoted at every GC etc. | |
|
||||||||
| -XX:+PrintGCTaskTimeStamps | bool | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:+PrintGCTimeStamps | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Prints the times at which the GCs happen relative to the start of the application | |
| -XX:+PrintHeapAtGC | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Prints detailed GC info including heap occupancy before and after GC. | |
| -XX:+PrintHeapAtSIGBREAK | bool | 1.6.0 | ||||||
| -XX:+PrintHeapUsageOverTime | bool | Print heap usage and capacity with timestamps | ||||||
| -XX:+PrintInlining | bool | Print message about inlined methods (debug only) | ||||||
| -XX:+PrintInterpreter | bool | 1.6.0 | ||||||
| -XX:+PrintJNIResolving | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+PrintParallelOldGCPhaseTimes | bool | 1.6.0 | ||||||
| -XX:+PrintParScavenge | bool | 1.3.1 | ||||||
| -XX:+PrintPLAB | bool | 1.6.0 | ||||||
| -XX:+PrintScavenge | bool | 1.3.1 | ||||||
| -XX:+PrintSharedSpaces | bool | 1.5.0 | 1.6.0 | |||||
| -XX:+PrintTenuringDistribution | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Gives the aging distribution of the allocated objects in the young generation. Tuning of -XX:NewSize, -XX:MaxNewSize, -XX:SurvivorRatio and -XX:MaxTenuringThreshold=0as described earlier, should be directed by the analysis of the output from this switch to determine that objects are not prematurely promoted to the old generation. |
|
||||||||
| -XX:+PrintTLAB | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | trace all the operations on TLAB's (Thread Allocation Buffers) | |
| -XX:+PrintTLE | bool | 1.3.1 | 1.6.0 | |||||
| -XX:+PrintVMOptions | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+PrintVMQWaitTime | bool | 1.6.0 | ||||||
| -XX:ProcessDistributionStride=<value> | uintx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:ProcessingToTenuringRatio=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | O | |
| -XX:+ProfileIntervals | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:ProfileIntervalsTicks=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:ProfileMaturityPercentage=<value> | intx | 1.6.0 | ||||||
| -XX:+ProfilerLight | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | ||
| -XX:+ProfilerPrintByteCodeStatistics | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+ProfilerRecordPC | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+ProfileVM | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:PromotedPadding=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:QueuedAllocationWarningCount=<value> | intx | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:+RangeCheckElimination | bool | 1.6.0 | ||||||
| -XX:ReadPrefetchInstr=<value> | intx | 1.6.0 | ||||||
| -XX:ReadSpinIterations=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+ReduceSignalUsage | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:RefDiscoveryPolicy=<value> | intx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:+RegisterFinalizersAtInit | bool | 1.6.0 | ||||||
| -XX:+RelaxAccessControlCheck | bool | 1.6.0 | ||||||
| -XX:+RequireSharedSpaces | bool | 1.5.0 | 1.6.0 | |||||
| -XX:ReservedCodeCacheSize=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Reserved code cache size (in bytes) - maximum code cache size. [Solaris 64-bit: 1024m] |
| -XX:+ResizePLAB | bool | 1.6.0 | ||||||
| -XX:+ResizeTLAB | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Enable or disable resizing of TLABs. The -server VM has this option enabled by default. | |
| -XX:+ResizeTLE | bool | 1.3.1 | 1.6.0 | |||||
| -XX:+RestoreMXCSROnJNICalls | bool | 1.6.0 | ||||||
| -XX:+RewriteBytecodes | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:+RewriteFrequentPairs | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+SafepointPolling | bool | 1.5.0 | ||||||
| -XX:SafepointSpinBeforeYield=<value> | intx | 1.6.0 | ||||||
| -XX:+ScavengeBeforeFullGC | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:ScavengeThreads=<value> | 1.3.1 | |||||||
| -XX:SelfDestructTimer=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+SerializeVMOutput | bool | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:SharedDummyBlockSize=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:SharedMiscDataSize=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:+SharedOptimizeColdStart | bool | 1.6.0 | ||||||
| -XX:SharedReadOnlySize=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:SharedReadWriteSize=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:+SharedSkipVerify | bool | 1.6.0 | ||||||
| -XX:+ShowMessageBoxOnError | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:SliceSizeInCards=<value> | 1.3.1 | |||||||
| -XX:SoftRefLRUPolicyMSPerMB=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Starting with Java HotSpot VM implementations in J2SE 1.3.1, softly reachable objects will remain alive for some amount of time after the last time they were referenced. The default value is one second of lifetime per free megabyte in the heap. This value can be adjusted using the -XX:SoftRefLRUPolicyMSPerMB flag, which accepts integer values representing milliseconds per MB of free memory. |
| -XX:+SplitIfBlocks | bool | 1.6.0 | ||||||
| -XX:StackRedPages=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:StackShadowPages=<value> | intx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:+StackTraceInThrowable | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Enable or disable stack traces in exceptions. |
| -XX:StackYellowPages=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:Stage2CompileThreshold=<value> | intx | 1.4.0 | ||||||
| -XX:+StagedCompilation | bool | 1.4.0 | ||||||
| -XX:+StartAttachListener | bool | 1.6.0 | ||||||
| -XX:StarvationMonitorInterval=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+StressLdcRewrite | bool | 1.6.0 | ||||||
| -XX:+StressTieredRuntime | bool | 1.6.0 | ||||||
| -XX:+SuppressFatalErrorMessage | bool | 1.6.0 | ||||||
| -XX:SurvivorPadding=<value> | uintx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:SurvivorRatio=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Sets the ratio of the survivor spaces (there are two) to the whole of the young generation. |
|
||||||||
| -XX:SuspendRetryCount=<value> | intx | 1.6.0 | ||||||
| -XX:SuspendRetryDelay=<value> | intx | 1.6.0 | ||||||
| -XX:SyncFlags=<value> | intx | 1.6.0 | ||||||
| -XX:SyncKnobs=<value> | ccstr | 1.6.0 | ||||||
| -XX:SyncVerbose=<value> | intx | 1.6.0 | ||||||
| -XX:+TaggedStackInterpreter | bool | 1.6.0 | ||||||
| -XX:TargetPLABWastePct=<value> | intx | 1.6.0 | ||||||
| -XX:TargetSurvivorOccupationRatio=<value> | size_t | 1.3.1 | ||||||
| -XX:TargetSurvivorPadding=<value> | size_t | 1.3.1 | ||||||
| -XX:TargetSurvivorRatio=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | This flag sets the desired percentage of the survivor space heap which must be used before objects are promoted to the old generation. For example, setting z to 90 would mean that 90% of the survivor space must be used before the young generation is considered full and objects are promoted to the old generation. This would allow objects to age more in the young generation before being tenured. The default value is 50. |
| -XX:TenuredGenerationSizeIncrement=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:TenuredGenerationSizeSupplement=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:TenuredGenerationSizeSupplementDecay=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:ThreadPriorityPolicy=<value> | intx | 1.5.0 | 1.6.0 | |||||
| -XX:+ThreadPriorityVerbose | bool | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:ThreadSafetyMargin=<value> | intx | 1.5.0 | 1.6.0 | |||||
| -XX:ThreadStackSize=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Thread Stack Size (in Kbytes) (0 means use default stack size) [Sparc: 512, Solaris Intel: 256, Sparc 64bit: 1024 all others 0] |
| -XX:ThresholdTolerance=<value> | uintx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:Tier1BytecodeLimit=<value> | intx | 1.6.0 | ||||||
| -XX:+Tier1UpdateMethodData | bool | 1.6.0 | ||||||
| -XX:Tier2BackEdgeThreshold=<value> | intx | 1.6.0 | ||||||
| -XX:Tier2CompileThreshold=<value> | intx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:+TieredCompilation | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:TLABAllocationWeight=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:TLABFragmentationRatio=<value> | uintx | 1.4.0 | 1.4.1 | 1.4.2 | ||||
| -XX:TLABRefillWasteFraction=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:TLABSize=<value> | uintx | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Set the size of the TLAB in bytes. | |
| -XX:+TLABStats | bool | 1.5.0 | 1.6.0 | |||||
| -XX:TLABThreadRatio=<value> | uintx | 1.4.0 | 1.4.1 | 1.4.2 | ||||
| -XX:TLABWasteIncrement=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:TLABWasteTargetPercent=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:TLEFragmentationRatio=<value> | 1.3.1 | 1.6.0 | ||||||
| -XX:TLESize=<value> | size_t | 1.3.1 | 1.6.0 | Sets the size of the TLEs (in bytes) | ||||
| -XX:TLEThreadRatio=<value> | 1.3.1 | 1.6.0 | ||||||
| -XX:+TraceBiasedLocking | bool | 1.6.0 | ||||||
| -XX:+TraceClassLoading | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Display classes as they are loaded. Similar to -verbose:class |
| -XX:+TraceClassLoadingPreorder | bool | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:+TraceClassResolution | bool | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:+TraceClassUnloading | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Display classes as they are unloaded. |
| -XX:+TraceFailedVMTextSegmentRetarget | bool | 1.4.0 | 1.4.1 | |||||
| -XX:+TraceGen0Time | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:+TraceGen1Time | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:TraceJVMTI=<value> | ccstr | 1.5.0 | 1.6.0 | |||||
| -XX:+TraceJVMTIObjectTagging | bool | 1.5.0 | 1.6.0 | |||||
| -XX:+TraceLoaderConstraints | bool | 1.6.0 | ||||||
| -XX:+TraceMonitorInflation | bool | 1.6.0 | ||||||
| -XX:+TraceParallelOldGCTasks | bool | 1.6.0 | ||||||
| -XX:TraceRedefineClasses=<value> | intx | 1.6.0 | ||||||
| -XX:TypeProfileFailureLimit=<value> | intx | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | |||
| -XX:TypeProfileMinimumRatio=<value> | intx | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:Ultra3PrefetchCopyIntervalInBytes=<value> | 1.3.1 | |||||||
| -XX:Ultra3PrefetchScanIntervalInBytes=<value> | 1.3.1 | |||||||
| -XX:Ultra3PrefetchScavengeFieldsAhead=<value> | 1.3.1 | |||||||
| -XX:UnguardOnExecutionViolation=<value> | intx | 1.6.0 | ||||||
| -XX:+UnlockDiagnosticVMOptions | bool | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:+Use486InstrsOnly | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:+UseAdaptiveGCBoundary | bool | 1.5.0 | 1.6.0 | |||||
| -XX:+UseAdaptiveGenerationSizePolicyAtMajorCollection | bool | 1.5.0 | 1.6.0 | |||||
| -XX:+UseAdaptiveGenerationSizePolicyAtMinorCollection | bool | 1.5.0 | 1.6.0 | |||||
| -XX:+UseAdaptiveNUMAChunkSizing | bool | 1.6.0 | ||||||
| -XX:+UseAdaptiveSizeDecayMajorGCCost | bool | 1.6.0 | ||||||
| -XX:+UseAdaptiveSizePolicy | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Automatically sizes the young generation and chooses an optimum survivor ratio to maximize performance. | ||
|
||||||||
| -XX:+UseAdaptiveSizePolicyAggressiveFootprintGoal | bool | 1.5.0 | ||||||
| -XX:+UseAdaptiveSizePolicyFootprintGoal | bool | 1.5.0 | 1.6.0 | |||||
| -XX:+UseAdaptiveSizePolicyWithSystemGC | bool | 1.5.0 | 1.6.0 | |||||
| -XX:+UseAdaptiveSizeScaleFootprintChangeByRatio | bool | 1.5.0 | ||||||
| -XX:+UseAdaptiveSizeScaleThroughputChangeByRatio | bool | 1.5.0 | ||||||
| -XX:+UseAltSigs | bool | 1.3.1 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | On the Solaris operating environment, the VM uses SIGUSR1 by default, which can sometimes conflict with applications that signal-chain SIGUSR1. -XX:+UseAltSigs will cause the VM to use signals other than SIGUSR1 and SIGUSR2 as the default. | |
| -XX:+UseAutoGCSelectPolicy | bool | 1.6.0 | ||||||
| -XX:+UseBiasedLocking | bool | 1.5.0 | 1.6.0 | This option first appears in 1.5.0_06. Enables a technique for improving the performance of uncontended synchronization. Some applications with significant amounts of uncontended synchronization may attain significant speedups with this flag enabled. | ||||
| -XX:+UseBoundThreads | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Bind user level threads (Solaris only) |
| -XX:+UseC2CallingConventions | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | |||
| -XX:+UseCMSBestFit | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:+UseCMSCollectionPassing | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:+UseCMSCompactAtFullCollection | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Normally the concurrent low pause collector does not copy nor compact the live objects. A garbage collection is done without moving the live objects. If fragmentation becomes a problem, allocate a larger heap. In 1.4.2 if fragmentation in the tenured generation becomes a problem, a compaction of the tenured generation will be done although not concurrently. In 1.4.1 that compaction will occur if the UseCMSCompactAtFullCollection option is turned on. | ||
| -XX:+UseCMSInitiatingOccupancyOnly | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Used to enabled/disable the use of the anticipated promotions to start a concurrent collection set | ||
| -XX:+UseCompiler | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:+UseCompilerSafepoints | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+UseConcMarkSweepGC | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | This flag turns on concurrent garbage collection in the old generation. Available from J2SE1.4.1. | |
|
||||||||
| -XX:+UseDefaultStackSize | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | ||
| -XX:+UseDepthFirstScavengeOrder | bool | 1.6.0 | ||||||
| -XX:+UseExtendedFileIO | bool | 1.6.0 | ||||||
| -XX:+UseFastAccessorMethods | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+UseFastEmptyMethods | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+UseFastJNIAccessors | bool | 1.5.0 | 1.6.0 | |||||
| -XX:+UseFixedFrameSize | bool | 1.4.0 | 1.4.1 | 1.4.2 | ||||
| -XX:+UseForcedSuspension | bool | 1.4.1 | 1.4.2 | |||||
| -XX:+UseGCOverheadLimit | bool | 1.6.0 | ||||||
| -XX:+UseGCTaskAffinity | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:+UseHeavyMonitors | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+UseInterpreter | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+UseISM | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Intimate Shared Memory |
| -XX:+UseLargePages | bool | 1.6.0 | ||||||
| -XX:+UseLargePageSize | bool | 1.4.0 | 1.4.1 | |||||
| -XX:+UseLoopCounter | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+UseLWPSynchronization | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Use LWP-based instead of thread based synchronization. Default is on in J2SE 1.4.0 or higher. (Solaris only) |
| -XX:+UseMaximumCompactionOnSystemGC | bool | 1.6.0 | ||||||
| -XX:+UseMembar | bool | 1.6.0 | ||||||
| -XX:+UseMPSS | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Use Multiple Page Size Support (Solaris 9 only) w/4mb pages for the heap. Do not use with ISM as this replaces the need for ISM. | |
| -XX:+UseNewCode | bool | 1.6.0 | ||||||
| -XX:+UseNewCode2 | bool | 1.6.0 | ||||||
| -XX:+UseNewCode3 | bool | 1.6.0 | ||||||
| -XX:+UseNewFeature1 | bool | 1.4.2 | 1.5.0 | |||||
| -XX:+UseNewFeature2 | bool | 1.4.2 | 1.5.0 | |||||
| -XX:+UseNewFeature3 | bool | 1.4.2 | 1.5.0 | |||||
| -XX:+UseNewFeature4 | bool | 1.4.2 | 1.5.0 | |||||
| -XX:+UseNiagaraInstrs | bool | 1.6.0 | ||||||
| -XX:+UseOnStackReplacement | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+UseOversizedCarHandling | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | O | ||
| -XX:+UseParallelDensePrefixUpdate | bool | 1.6.0 | ||||||
| -XX:+UseParallelGC | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | This flag also turns on parallel garbage collection policy in the young generation; however, it does not work with the CMS collector in the old generation. It is more suitable for enterprise applications which can benefit from very large young generation heaps. | ||
|
||||||||
| -XX:+UseParallelOldGC | bool | 1.6.0 | ||||||
| -XX:+UseParallelOldGCCompacting | bool | 1.6.0 | ||||||
| -XX:+UseParallelOldGCDensePrefix | bool | 1.6.0 | ||||||
| -XX:+UseParallelScavenge | bool | 1.3.1 | ||||||
| -XX:+UseParNewGC | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | This flag turns on parallel garbage collection in the young generation. It can be enabled together with the CMS collector in the old generation. Available in J2SE1.4.1 on an experimental basis. | ||
|
||||||||
| -XX:+UsePerfData | bool | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:+UsePermISM | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+UsePSAdaptiveSurvivorSizePolicy | bool | 1.5.0 | 1.6.0 | |||||
| -XX:+UseRecompilation | bool | 1.3.1 | ||||||
| -XX:+UseResizableSurvivorSpaces | bool | 1.3.1 | ||||||
| -XX:+UseSerialGC | bool | 1.5.0 | 1.6.0 | Enable the "legacy" serial garbage collector. The 1.5+ collectors are generally more robust now, and this garbage collector will not be supported much longer | ||||
| -XX:+UseSharedSpaces | bool | 1.5.0 | 1.6.0 | |||||
| -XX:+UseSignalChaining | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+UseSpecLock | bool | 1.3.1 | 1.4.0 | |||||
| -XX:+UseSpinning | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+UseSplitVerifier | bool | 1.5.0 | 1.6.0 | |||||
| -XX:UseSSE=<value> | intx | 1.5.0 | 1.6.0 | From Bug 5108893, The option probably indicates whether the compiler should make use of the processor's SSEi instructions and is only available in server VMs. | ||||
| -XX:+UseStoreImmI16 | bool | 1.6.0 | ||||||
| -XX:+UseSuspendResumeThreadLists | bool | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:+UseThreadPriorities | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Use native thread priorities |
| -XX:+UseTLAB | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | Turn off thread-local object allocation | |
| -XX:+UseTLE | bool | 1.3.1 | 1.6.0 | Turn off thread local portions of the heap in the young generation | ||||
| -XX:+UseTrainGC | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | O | |
| -XX:+UseTypeProfile | bool | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:+UseUnsupportedDeprecatedJVMPI | bool | 1.6.0 | ||||||
| -XX:+UseVectoredExceptions | bool | 1.6.0 | ||||||
| -XX:+UseVMInterruptibleIO | bool | 1.6.0 | ||||||
| -XX:ValueMapBucketInitialSize=<value> | intx | 1.4.0 | ||||||
| -XX:ValueMapBucketMaxSize=<value> | intx | 1.4.0 | ||||||
| -XX:ValueMapMaxSize=<value> | intx | 1.4.0 | ||||||
| -XX:+VerifyAfterGC | bool | 1.6.0 | ||||||
| -XX:+VerifyAfterScavenge | bool | |||||||
| -XX:+VerifyBeforeExit | bool | 1.6.0 | ||||||
| -XX:+VerifyBeforeGC | bool | 1.6.0 | ||||||
| -XX:+VerifyBeforeIteration | bool | 1.5.0 | 1.6.0 | |||||
| -XX:+VerifyBeforeScavenge | bool | |||||||
| -XX:+VerifyDuringGC | bool | 1.6.0 | ||||||
| -XX:VerifyGCLevel=<value> | intx | 1.6.0 | ||||||
| -XX:+VerifyMergedCPBytecodes | bool | 1.6.0 | ||||||
| -XX:+VerifyObjectStartArray | bool | 1.6.0 | ||||||
| -XX:+VerifyRememberedSets | bool | 1.6.0 | ||||||
| -XX:+VerifyTLAB | bool | 1.4.2 | ||||||
| -XX:+VerifyTLE | bool | |||||||
| -XX:+VMThreadHintNoPreempt | bool | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:VMThreadPriority=<value> | intx | 1.4.2 | 1.5.0 | 1.6.0 | ||||
| -XX:VMThreadStackSize=<value> | intx | 1.3.1 | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |
| -XX:WorkAroundNPTLTimedWaitHang=<value> | intx | 1.6.0 | ||||||
| -XX:YoungGenerationSizeIncrement=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:YoungGenerationSizeSupplement=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:YoungGenerationSizeSupplementDecay=<value> | uintx | 1.5.0 | 1.6.0 | |||||
| -XX:YoungPLABSize=<value> | uintx | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | |||
| -XX:+ZeroTLAB | bool | 1.4.0 | 1.4.1 | 1.4.2 | 1.5.0 | 1.6.0 | ||
| -XX:+ZeroTLE | bool | 1.3.1 | ||||||
References:
- JVM Performance Documentation
- Analyzing Stack Traces
- Turbo-charging Java HotSpot Virtual Machine
- Java HotSpot VM Options
- Tuning Garbage Collection with the 1.3.1 Java Virtual Machine
- Java and Solaris Threading
- Frequently Asked Questions about Garbage Collection in the HotspotTM JavaTM Virtual Machine
- Tuning Garbage Collection with the 1.4.2 Java[tm] Virtual Machine
- Improving Java Application Performance and Scalability by Reducing Garbage Collection Times and Sizing Memory Using JDK 1.4.1
- Big Heaps and Intimate Shared Memory (ISM)
- A Test of Java Virtual Machine Performance
- HotSpot Performance Tuning
- The Java HotSpot Virtual Machine Client Compiler
- Java Developer Connection Bug Parade
- SDK release notes 1.3.1.12
- JavaTM Virtual Machine Profiler Interface (JVMPI)
- Garbage Collector Ergonomics
- Java Developer Connection Forums
- Frequently Asked Questions About the Java HotSpot VM
- Java HotSpotTM Server VM Version 2.0 for Win32 Platforms
- J2SE 1.5 in a Nutshell
- 1.4.2 HotSpot Instrumentation
- HotSpot Technology Tools and HP-Specific Features
- Diagnosing a Garbage Collection problem
- GC Portal
- HotSpot Performance Tuning
- Java HotSpot VM Options (docs.sun.com)
- Java Tuning White Paper
