JVM -XX -X Options

-XX:

 Reprint:http://stas-blogspot.blogspot.com/2011/07/most-complete-list-of-xx-options-for.html

Name	Description	Default	Type
product
UseMembar	(Unstable) Issues membars on thread state transitions	false	bool
UnlockCommercialFeatures	Enables Oracle Java SE users to control when licensed features are allowed to run. Since Java SE 7 Update 4.	false	bool
PrintCommandLineFlags	Prints flags that appeared on the command line	false	bool
UseGCLogFileRotation	Prevent large gclog file for long running app. Requires -Xloggc:. Since Java7.	false	bool
NumberOfGCLogFiles	Number of gclog files in rotation. Default: 0, no rotation. Only valid with UseGCLogFileRotation. Since Java7.	0	uintx
GCLogFileSize	GC log file size, Default: 0 bytes, no rotation. Only valid with UseGCLogFileRotation. Since Java7.	0	uintx
JavaMonitorsInStackTrace	Print info. about Java monitor locks when the stacks are dumped	true	bool
LargePageSizeInBytes	Large page size (0 to let VM choose the page size	0	uintx
LargePageHeapSizeThreshold	Use large pages if max heap is at least this big	128*M	uintx
ForceTimeHighResolution	Using high time resolution(For Win32 only)	false	bool
PrintVMQWaitTime	Prints out the waiting time in VM operation queue	false	bool
PrintJNIResolving	Used to implement -v:jni	false	bool
UseInlineCaches	Use Inline Caches for virtual calls	true	bool
UseCompilerSafepoints	Stop at safepoints in compiled code	true	bool
UseSplitVerifier	use split verifier with StackMapTable attributes	true	bool
FailOverToOldVerifier	fail over to old verifier when split verifier fails	true	bool
SuspendRetryCount	Maximum retry count for an external suspend request	50	intx
SuspendRetryDelay	Milliseconds to delay per retry (* current_retry_count)	5	intx
UseSuspendResumeThreadLists	Enable SuspendThreadList and ResumeThreadList	true	bool
MaxFDLimit	Bump the number of file descriptors to max in solaris.	true	bool
BytecodeVerificationRemote	Enables the Java bytecode verifier for remote classes	true	bool
BytecodeVerificationLocal	Enables the Java bytecode verifier for local classes	false	bool
PrintGCApplicationConcurrentTime	Print the time the application has been running	false	bool
PrintGCApplicationStoppedTime	Print the time the application has been stopped	false	bool
ShowMessageBoxOnError	Keep process alive on VM fatal error	false	bool
SuppressFatalErrorMessage	Do NO Fatal Error report [Avoid deadlock]	false	bool
OnError	Run user-defined commands on fatal error; see VMError.cpp for examples	""	ccstr
OnOutOfMemoryError	Run user-defined commands on first java.lang.OutOfMemoryError	""	ccstr
PrintCompilation	Print compilations	false	bool
StackTraceInThrowable	Collect backtrace in throwable when exception happens	true	bool
OmitStackTraceInFastThrow	Omit backtraces for some 'hot' exceptions in optimized code	true	bool
ProfilerPrintByteCodeStatistics	Prints byte code statictics when dumping profiler output	false	bool
ProfilerRecordPC	Collects tick for each 16 byte interval of compiled code	false	bool
UseNUMA	Enables NUMA support. See details here	false	bool
ProfileVM	Profiles ticks that fall within VM (either in the VM Thread or VM code called through stubs)	false	bool
ProfileIntervals	Prints profiles for each interval (see ProfileIntervalsTicks)	false	bool
RegisterFinalizersAtInit	Register finalizable objects at end of Object. or after allocation.	true	bool
ClassUnloading	Do unloading of classes	true	bool
ConvertYieldToSleep	Converts yield to a sleep of MinSleepInterval to simulate Win32 behavior (SOLARIS only)	false	bool
UseBoundThreads	Bind user level threads to kernel threads (for SOLARIS only)	true	bool
UseLWPSynchronization	Use LWP-based instead of libthread-based synchronization (SPARC only)	true	bool
SyncKnobs	(Unstable) Various monitor synchronization tunables	""	ccstr
EmitSync	(Unsafe,Unstable) Controls emission of inline sync fast-path code	0	intx
AlwaysInflate	(Unstable) Force inflation	0	intx
Atomics	(Unsafe,Unstable) Diagnostic - Controls emission of atomics	0	intx
EmitLFence	(Unsafe,Unstable) Experimental	0	intx
AppendRatio	(Unstable) Monitor queue fairness" ) product(intx, SyncFlags, 0,(Unsafe,Unstable) Experimental Sync flags" ) product(intx, SyncVerbose, 0,(Unstable)" ) product(intx, ClearFPUAtPark, 0,(Unsafe,Unstable)" ) product(intx, hashCode, 0, (Unstable) select hashCode generation algorithm" ) product(intx, WorkAroundNPTLTimedWaitHang, 1, (Unstable, Linux-specific)" avoid NPTL-FUTEX hang pthread_cond_timedwait" ) product(bool, FilterSpuriousWakeups , true, Prevent spurious or premature wakeups from object.wait" (Solaris only)	11	intx
AdjustConcurrency	call thr_setconcurrency at thread create time to avoid LWP starvation on MP systems (For Solaris Only)	false	bool
ReduceSignalUsage	Reduce the use of OS signals in Java and/or the VM	false	bool
AllowUserSignalHandlers	Do not complain if the application installs signal handlers (Solaris & Linux only)	false	bool
UseSignalChaining	Use signal-chaining to invoke signal handlers installed by the application (Solaris & Linux only)	true	bool
UseAltSigs	Use alternate signals instead of SIGUSR1 & SIGUSR2 for VM internal signals. (Solaris only)	false	bool
UseSpinning	Use spinning in monitor inflation and before entry	false	bool
PreSpinYield	Yield before inner spinning loop	false	bool
PostSpinYield	Yield after inner spinning loop	true	bool
UsePopCountInstruction	Where possible replaces call to Integer.bitCount() with assembly instruction, i.e. POCCNT on Intel, POPC on Sparc, etc	true	bool
AllowJNIEnvProxy	Allow JNIEnv proxies for jdbx	false	bool
JNIDetachReleasesMonitors	JNI DetachCurrentThread releases monitors owned by thread	true	bool
RestoreMXCSROnJNICalls	Restore MXCSR when returning from JNI calls	false	bool
CheckJNICalls	Verify all arguments to JNI calls	false	bool
UseFastJNIAccessors	Use optimized versions of GetField	true	bool
EagerXrunInit	Eagerly initialize -Xrun libraries; allows startup profiling, but not all -Xrun libraries may support the state of the VM at this time	false	bool
PreserveAllAnnotations	Preserve RuntimeInvisibleAnnotations as well as RuntimeVisibleAnnotations	false	bool
LazyBootClassLoader	Enable/disable lazy opening of boot class path entries	true	bool
UseBiasedLocking	Enable biased locking in JVM	true	bool
BiasedLockingStartupDelay	Number of milliseconds to wait before enabling biased locking	4000	intx
BiasedLockingBulkRebiasThreshold	Threshold of number of revocations per type to try to rebias all objects in the heap of that type	20	intx
BiasedLockingBulkRevokeThreshold	Threshold of number of revocations per type to permanently revoke biases of all objects in the heap of that type	40	intx
BiasedLockingDecayTime	Decay time (in milliseconds) to re-enable bulk rebiasing of a type after previous bulk rebias	25000	intx
TraceJVMTI	Trace flags for JVMTI functions and events	""	ccstr
StressLdcRewrite	Force ldc -> ldc_w rewrite during RedefineClasses	false	bool
TraceRedefineClasses	Trace level for JVMTI RedefineClasses	0	intx
VerifyMergedCPBytecodes	Verify bytecodes after RedefineClasses constant pool merging	true	bool
HPILibPath	Specify alternate path to HPI library	""	ccstr
TraceClassResolution	Trace all constant pool resolutions (for debugging)	false	bool
TraceBiasedLocking	Trace biased locking in JVM	false	bool
TraceMonitorInflation	Trace monitor inflation in JVM	false	bool
Use486InstrsOnly	Use 80486 Compliant instruction subset	false	bool
UseSerialGC	Tells whether the VM should use serial garbage collector	false	bool
UseParallelGC	Use parallel garbage collection for scavenges. (Introduced in 1.4.1)	true	bool
UseParallelOldGC	Use parallel garbage collection for the full collections. Enabling this option automatically sets -XX:+UseParallelGC. (Introduced in 5.0 update 6)	'false' before Java 7 update 4 and 'true' after that version	bool
UseParallelOldGCCompacting	In the Parallel Old garbage collector use parallel compaction	true	bool
UseParallelDensePrefixUpdate	In the Parallel Old garbage collector use parallel dense" prefix update	true	bool
HeapMaximumCompactionInterval	How often should we maximally compact the heap (not allowing any dead space)	20	uintx
HeapFirstMaximumCompactionCount	The collection count for the first maximum compaction	3	uintx
UseMaximumCompactionOnSystemGC	In the Parallel Old garbage collector maximum compaction for a system GC	true	bool
ParallelOldDeadWoodLimiterMean	The mean used by the par compact dead wood" limiter (a number between 0-100).	50	uintx
ParallelOldDeadWoodLimiterStdDev	The standard deviation used by the par compact dead wood" limiter (a number between 0-100).	80	uintx
UseParallelOldGCDensePrefix	Use a dense prefix with the Parallel Old garbage collector	true	bool
ParallelGCThreads	Number of parallel threads parallel gc will use	0	uintx
ParallelCMSThreads	Max number of threads CMS will use for concurrent work	0	uintx
YoungPLABSize	Size of young gen promotion labs (in HeapWords)	4096	uintx
OldPLABSize	Size of old gen promotion labs (in HeapWords).  See good explanation about that parameter here.	1024	uintx
GCTaskTimeStampEntries	Number of time stamp entries per gc worker thread	200	uintx
AlwaysTenure	Always tenure objects in eden. (ParallelGC only)	false	bool
NeverTenure	Never tenure objects in eden, May tenure on overflow" (ParallelGC only)	false	bool
ScavengeBeforeFullGC	Scavenge youngest generation before each full GC," used with UseParallelGC	true	bool
UseCompressedOops	Enables object-reference compression capabilities via the Compressed References. Have sense just on 64bit JVM. See more details here.	false	bool
UseConcMarkSweepGC	Use Concurrent Mark-Sweep GC in the old generation	false	bool
ExplicitGCInvokesConcurrent	A System.gc() request invokes a concurrent collection;" (effective only when UseConcMarkSweepGC)	false	bool
UseCMSBestFit	Use CMS best fit allocation strategy	true	bool
UseCMSCollectionPassing	Use passing of collection from background to foreground	true	bool
UseParNewGC	Use parallel threads in the new generation.	false	bool
ParallelGCVerbose	Verbose output for parallel GC.	false	bool
ParallelGCBufferWastePct	wasted fraction of parallel allocation buffer.	10	intx
ParallelGCRetainPLAB	Retain parallel allocation buffers across scavenges.	true	bool
TargetPLABWastePct	target wasted space in last buffer as pct of overall allocation	10	intx
PLABWeight	Percentage (0-100) used to weight the current sample when" computing exponentially decaying average for ResizePLAB.	75	uintx
ResizePLAB	Dynamically resize (survivor space) promotion labs	true	bool
PrintPLAB	Print (survivor space) promotion labs sizing decisions	false	bool
ParGCArrayScanChunk	Scan a subset and push remainder, if array is bigger than this	50	intx
ParGCDesiredObjsFromOverflowList	The desired number of objects to claim from the overflow list	20	intx
CMSParPromoteBlocksToClaim	Number of blocks to attempt to claim when refilling CMS LAB for parallel GC.	50	uintx
AlwaysPreTouch	It forces all freshly committed pages to be pre-touched.	false	bool
CMSUseOldDefaults	A flag temporarily introduced to allow reverting to some older" default settings; older as of 6.0	false	bool
CMSYoungGenPerWorker	The amount of young gen chosen by default per GC worker thread available	16*M	intx
CMSIncrementalMode	Whether CMS GC should operate in \"incremental\" mode	false	bool
CMSIncrementalDutyCycle	CMS incremental mode duty cycle (a percentage, 0-100). If" CMSIncrementalPacing is enabled, then this is just the initial" value	10	uintx
CMSIncrementalPacing	Whether the CMS incremental mode duty cycle should be automatically adjusted	true	bool
CMSIncrementalDutyCycleMin	Lower bound on the duty cycle when CMSIncrementalPacing is" enabled (a percentage, 0-100).	0	uintx
CMSIncrementalSafetyFactor	Percentage (0-100) used to add conservatism when computing the" duty cycle.	10	uintx
CMSIncrementalOffset	Percentage (0-100) by which the CMS incremental mode duty cycle" is shifted to the right within the period between young GCs	0	uintx
CMSExpAvgFactor	Percentage (0-100) used to weight the current sample when" computing exponential averages for CMS statistics.	25	uintx
CMS_FLSWeight	Percentage (0-100) used to weight the current sample when" computing exponentially decating averages for CMS FLS statistics.	50	uintx
CMS_FLSPadding	The multiple of deviation from mean to use for buffering" against volatility in free list demand.	2	uintx
FLSCoalescePolicy	CMS: Aggression level for coalescing, increasing from 0 to 4	2	uintx
CMS_SweepWeight	Percentage (0-100) used to weight the current sample when" computing exponentially decaying average for inter-sweep duration.	50	uintx
CMS_SweepPadding	The multiple of deviation from mean to use for buffering" against volatility in inter-sweep duration.	2	uintx
CMS_SweepTimerThresholdMillis	Skip block flux-rate sampling for an epoch unless inter-sweep duration exceeds this threhold in milliseconds	10	uintx
CMSClassUnloadingEnabled	Whether class unloading enabled when using CMS GC	false	bool
CMSCompactWhenClearAllSoftRefs	Compact when asked to collect CMS gen with clear_all_soft_refs	true	bool
UseCMSCompactAtFullCollection	Use mark sweep compact at full collections	true	bool
CMSFullGCsBeforeCompaction	Number of CMS full collection done before compaction if > 0	0	uintx
CMSIndexedFreeListReplenish	Replenish and indexed free list with this number of chunks	4	uintx
CMSLoopWarn	Warn in case of excessive CMS looping	false	bool
CMSMarkStackSize	Size of CMS marking stack	32*K	uintx
CMSMarkStackSizeMax	Max size of CMS marking stack	4*M	uintx
CMSMaxAbortablePrecleanLoops	(Temporary, subject to experimentation)" Maximum number of abortable preclean iterations, if > 0	0	uintx
CMSMaxAbortablePrecleanTime	(Temporary, subject to experimentation)" Maximum time in abortable preclean in ms	5000	intx
CMSAbortablePrecleanMinWorkPerIteration	(Temporary, subject to experimentation)" Nominal minimum work per abortable preclean iteration	100	uintx
CMSAbortablePrecleanWaitMillis	(Temporary, subject to experimentation)" Time that we sleep between iterations when not given" enough work per iteration	100	intx
CMSRescanMultiple	Size (in cards) of CMS parallel rescan task	32	uintx
CMSConcMarkMultiple	Size (in cards) of CMS concurrent MT marking task	32	uintx
CMSRevisitStackSize	Size of CMS KlassKlass revisit stack	1*M	uintx
CMSAbortSemantics	Whether abort-on-overflow semantics is implemented	false	bool
CMSParallelRemarkEnabled	Whether parallel remark enabled (only if ParNewGC)	true	bool
CMSParallelSurvivorRemarkEnabled	Whether parallel remark of survivor space" enabled (effective only if CMSParallelRemarkEnabled)	true	bool
CMSPLABRecordAlways	Whether to always record survivor space PLAB bdries" (effective only if CMSParallelSurvivorRemarkEnabled)	true	bool
CMSConcurrentMTEnabled	Whether multi-threaded concurrent work enabled (if ParNewGC)	true	bool
CMSPermGenPrecleaningEnabled	Whether concurrent precleaning enabled in perm gen" (effective only when CMSPrecleaningEnabled is true)	true	bool
CMSPermGenSweepingEnabled	Whether sweeping of perm gen is enabled	false	bool
CMSPrecleaningEnabled	Whether concurrent precleaning enabled	true	bool
CMSPrecleanIter	Maximum number of precleaning iteration passes	3	uintx
CMSPrecleanNumerator	CMSPrecleanNumerator:CMSPrecleanDenominator yields convergence" ratio	2	uintx
CMSPrecleanDenominator	CMSPrecleanNumerator:CMSPrecleanDenominator yields convergence" ratio	3	uintx
CMSPrecleanRefLists1	Preclean ref lists during (initial) preclean phase	true	bool
CMSPrecleanRefLists2	Preclean ref lists during abortable preclean phase	false	bool
CMSPrecleanSurvivors1	Preclean survivors during (initial) preclean phase	false	bool
CMSPrecleanSurvivors2	Preclean survivors during abortable preclean phase	true	bool
CMSPrecleanThreshold	Don't re-iterate if #dirty cards less than this	1000	uintx
CMSCleanOnEnter	Clean-on-enter optimization for reducing number of dirty cards	true	bool
CMSRemarkVerifyVariant	Choose variant (1,2) of verification following remark	1	uintx
CMSScheduleRemarkEdenSizeThreshold	If Eden used is below this value, don't try to schedule remark	2*M	uintx
CMSScheduleRemarkEdenPenetration	The Eden occupancy % at which to try and schedule remark pause	50	uintx
CMSScheduleRemarkSamplingRatio	Start sampling Eden top at least before yg occupancy reaches" 1/ of the size at which we plan to schedule remark	5	uintx
CMSSamplingGrain	The minimum distance between eden samples for CMS (see above)	16*K	uintx
CMSScavengeBeforeRemark	Attempt scavenge before the CMS remark step	false	bool
CMSWorkQueueDrainThreshold	Don't drain below this size per parallel worker/thief	10	uintx
CMSWaitDuration	Time in milliseconds that CMS thread waits for young GC	2000	intx
CMSYield	Yield between steps of concurrent mark & sweep	true	bool
CMSBitMapYieldQuantum	Bitmap operations should process at most this many bits" between yields	10*M	uintx
BlockOffsetArrayUseUnallocatedBlock	Maintain _unallocated_block in BlockOffsetArray" (currently applicable only to CMS collector)	trueInDebug	bool
RefDiscoveryPolicy	Whether reference-based(0) or referent-based(1)	0	intx
ParallelRefProcEnabled	Enable parallel reference processing whenever possible	false	bool
CMSTriggerRatio	Percentage of MinHeapFreeRatio in CMS generation that is allocated before a CMS collection cycle commences	80	intx
CMSBootstrapOccupancy	Percentage CMS generation occupancy at which to initiate CMS collection for bootstrapping collection stats	50	intx
CMSInitiatingOccupancyFraction	Percentage CMS generation occupancy to start a CMS collection cycle (A negative value means that CMSTirggerRatio is used). See good explanation about that parameter here.	-1	intx
UseCMSInitiatingOccupancyOnly	Only use occupancy as a crierion for starting a CMS collection.  See good explanation about that parameter here.	false	bool
HandlePromotionFailure	The youngest generation collection does not require" a guarantee of full promotion of all live objects.	true	bool
PreserveMarkStackSize	Size for stack used in promotion failure handling	40	uintx
ZeroTLAB	Zero out the newly created TLAB	false	bool
PrintTLAB	Print various TLAB related information	false	bool
TLABStats	Print various TLAB related information	true	bool
AlwaysActAsServerClassMachine	Always act like a server-class machine	false	bool
DefaultMaxRAM	Maximum real memory size for setting server class heap size	G	uintx
DefaultMaxRAMFraction	Fraction (1/n) of real memory used for server class max heap	4	uintx
DefaultInitialRAMFraction	Fraction (1/n) of real memory used for server class initial heap	64	uintx
UseAutoGCSelectPolicy	Use automatic collection selection policy	false	bool
AutoGCSelectPauseMillis	Automatic GC selection pause threshhold in ms	5000	uintx
UseAdaptiveSizePolicy	Use adaptive generation sizing policies	true	bool
UsePSAdaptiveSurvivorSizePolicy	Use adaptive survivor sizing policies	true	bool
UseAdaptiveGenerationSizePolicyAtMinorCollection	Use adaptive young-old sizing policies at minor collections	true	bool
UseAdaptiveGenerationSizePolicyAtMajorCollection	Use adaptive young-old sizing policies at major collections	true	bool
UseAdaptiveSizePolicyWithSystemGC	Use statistics from System.GC for adaptive size policy	false	bool
UseAdaptiveGCBoundary	Allow young-old boundary to move	false	bool
AdaptiveSizeThroughPutPolicy	Policy for changeing generation size for throughput goals	0	uintx
AdaptiveSizePausePolicy	Policy for changing generation size for pause goals	0	uintx
AdaptiveSizePolicyInitializingSteps	Number of steps where heuristics is used before data is used	20	uintx
AdaptiveSizePolicyOutputInterval	Collecton interval for printing information, zero => never	0	uintx
UseAdaptiveSizePolicyFootprintGoal	Use adaptive minimum footprint as a goal	true	bool
AdaptiveSizePolicyWeight	Weight given to exponential resizing, between 0 and 100	10	uintx
AdaptiveTimeWeight	Weight given to time in adaptive policy, between 0 and 100	25	uintx
PausePadding	How much buffer to keep for pause time	1	uintx
PromotedPadding	How much buffer to keep for promotion failure	3	uintx
SurvivorPadding	How much buffer to keep for survivor overflow	3	uintx
AdaptivePermSizeWeight	Weight for perm gen exponential resizing, between 0 and 100	20	uintx
PermGenPadding	How much buffer to keep for perm gen sizing	3	uintx
ThresholdTolerance	Allowed collection cost difference between generations	10	uintx
AdaptiveSizePolicyCollectionCostMargin	If collection costs are within margin, reduce both by full delta	50	uintx
YoungGenerationSizeIncrement	Adaptive size percentage change in young generation	20	uintx
YoungGenerationSizeSupplement	Supplement to YoungedGenerationSizeIncrement used at startup	80	uintx
YoungGenerationSizeSupplementDecay	Decay factor to YoungedGenerationSizeSupplement	8	uintx
TenuredGenerationSizeIncrement	Adaptive size percentage change in tenured generation	20	uintx
TenuredGenerationSizeSupplement	Supplement to TenuredGenerationSizeIncrement used at startup	80	uintx
TenuredGenerationSizeSupplementDecay	Decay factor to TenuredGenerationSizeIncrement	2	uintx
MaxGCPauseMillis	Adaptive size policy maximum GC pause time goal in msec	max_uintx	uintx
MaxGCMinorPauseMillis	Adaptive size policy maximum GC minor pause time goal in msec	max_uintx	uintx
GCTimeRatio	Adaptive size policy application time to GC time ratio	99	uintx
AdaptiveSizeDecrementScaleFactor	Adaptive size scale down factor for shrinking	4	uintx
UseAdaptiveSizeDecayMajorGCCost	Adaptive size decays the major cost for long major intervals	true	bool
AdaptiveSizeMajorGCDecayTimeScale	Time scale over which major costs decay	10	uintx
MinSurvivorRatio	Minimum ratio of young generation/survivor space size	3	uintx
InitialSurvivorRatio	Initial ratio of eden/survivor space size	8	uintx
BaseFootPrintEstimate	Estimate of footprint other than Java Heap	256*M	uintx
UseGCOverheadLimit	Use policy to limit of proportion of time spent in GC before an OutOfMemory error is thrown	true	bool
GCTimeLimit	Limit of proportion of time spent in GC before an OutOfMemory" error is thrown (used with GCHeapFreeLimit)	98	uintx
GCHeapFreeLimit	Minimum percentage of free space after a full GC before an OutOfMemoryError is thrown (used with GCTimeLimit)	2	uintx
PrintAdaptiveSizePolicy	Print information about AdaptiveSizePolicy	false	bool
DisableExplicitGC	Tells whether calling System.gc() does a full GC	false	bool
CollectGen0First	Collect youngest generation before each full GC	false	bool
BindGCTaskThreadsToCPUs	Bind GCTaskThreads to CPUs if possible	false	bool
UseGCTaskAffinity	Use worker affinity when asking for GCTasks	false	bool
ProcessDistributionStride	Stride through processors when distributing processes	4	uintx
CMSCoordinatorYieldSleepCount	number of times the coordinator GC thread will sleep while yielding before giving up and resuming GC	10	uintx
CMSYieldSleepCount	number of times a GC thread (minus the coordinator) will sleep while yielding before giving up and resuming GC	0	uintx
PrintGCTaskTimeStamps	Print timestamps for individual gc worker thread tasks	false	bool
TraceClassLoadingPreorder	Trace all classes loaded in order referenced (not loaded)	false	bool
TraceGen0Time	Trace accumulated time for Gen 0 collection	false	bool
TraceGen1Time	Trace accumulated time for Gen 1 collection	false	bool
PrintTenuringDistribution	Print tenuring age information	false	bool
PrintHeapAtSIGBREAK	Print heap layout in response to SIGBREAK	true	bool
TraceParallelOldGCTasks	Trace multithreaded GC activity	false	bool
PrintParallelOldGCPhaseTimes	Print the time taken by each parallel old gc phase." PrintGCDetails must also be enabled.	false	bool
CITime	collect timing information for compilation	false	bool
Inline	enable inlining	true	bool
ClipInlining	clip inlining if aggregate method exceeds DesiredMethodLimit	true	bool
UseTypeProfile	Check interpreter profile for historically monomorphic calls	true	bool
TypeProfileMinimumRatio	Minimum ratio of profiled majority type to all minority types	9	intx
Tier1UpdateMethodData	Update methodDataOops in Tier1-generated code	false	bool
PrintVMOptions	print VM flag settings	trueInDebug	bool
ErrorFile	If an error occurs, save the error data to this file [default: ./hs_err_pid%p.log] (%p replaced with pid)	""	ccstr
DisplayVMOutputToStderr	If DisplayVMOutput is true, display all VM output to stderr	false	bool
DisplayVMOutputToStdout	If DisplayVMOutput is true, display all VM output to stdout	false	bool
UseHeavyMonitors	use heavyweight instead of lightweight Java monitors	false	bool
RangeCheckElimination	Split loop iterations to eliminate range checks	true	bool
SplitIfBlocks	Clone compares and control flow through merge points to fold some branches	true	bool
AggressiveOpts	Enable aggressive optimizations - see arguments.cpp	false	bool
PrintInterpreter	Prints the generated interpreter code	false	bool
UseInterpreter	Use interpreter for non-compiled methods	true	bool
UseNiagaraInstrs	Use Niagara-efficient instruction subset	false	bool
UseLoopCounter	Increment invocation counter on backward branch	true	bool
UseFastEmptyMethods	Use fast method entry code for empty methods	true	bool
UseFastAccessorMethods	Use fast method entry code for accessor methods	true	bool
EnableJVMPIInstructionStartEvent	Enable JVMPI_EVENT_INSTRUCTION_START events - slows down interpretation	false	bool
JVMPICheckGCCompatibility	If JVMPI is used, make sure that we are using a JVMPI-compatible garbage collector	true	bool
ProfileMaturityPercentage	number of method invocations/branches (expressed as % of CompileThreshold) before using the method's profile	20	intx
UseCompiler	use compilation	true	bool
UseCounterDecay	adjust recompilation counters	true	bool
AlwaysCompileLoopMethods	when using recompilation, never interpret methods containing loops	false	bool
DontCompileHugeMethods	don't compile methods > HugeMethodLimit	true	bool
EstimateArgEscape	Analyze bytecodes to estimate escape state of arguments	true	bool
BCEATraceLevel	How much tracing to do of bytecode escape analysis estimates	0	intx
MaxBCEAEstimateLevel	Maximum number of nested calls that are analyzed by BC EA.	5	intx
MaxBCEAEstimateSize	Maximum bytecode size of a method to be analyzed by BC EA.	150	intx
SelfDestructTimer	Will cause VM to terminate after a given time (in minutes) (0 means off)	0	intx
MaxJavaStackTraceDepth	Max. no. of lines in the stack trace for Java exceptions (0 means all). With Java > 1.6, value 0 really means 0. value -1 or any negative number must be specified to print all the stack (tested with 1.6.0_22, 1.7.0 on Windows). With Java <= 1.5, value 0 means everything, JVM chokes on negative number (tested with 1.5.0_22 on Windows).	1024	intx
NmethodSweepFraction	Number of invocations of sweeper to cover all nmethods	4	intx
MaxInlineSize	maximum bytecode size of a method to be inlined	35	intx
ProfileIntervalsTicks	# of ticks between printing of interval profile (+ProfileIntervals)	100	intx
EventLogLength	maximum nof events in event log	2000	intx
PerMethodRecompilationCutoff	After recompiling N times, stay in the interpreter (-1=>'Inf')	400	intx
PerBytecodeRecompilationCutoff	Per-BCI limit on repeated recompilation (-1=>'Inf')	100	intx
PerMethodTrapLimit	Limit on traps (of one kind) in a method (includes inlines)	100	intx
PerBytecodeTrapLimit	Limit on traps (of one kind) at a particular BCI	4	intx
AliasLevel	0 for no aliasing, 1 for oop/field/static/array split, 2 for best	2	intx
ReadSpinIterations	Number of read attempts before a yield (spin inner loop)	100	intx
PreBlockSpin	Number of times to spin in an inflated lock before going to an OS lock	10	intx
MaxHeapSize	Default maximum size for object heap (in bytes)	ScaleForWordSize (64*M)	uintx
MaxNewSize	Maximum size of new generation (in bytes)	max_uintx	uintx
PretenureSizeThreshold	Max size in bytes of objects allocated in DefNew generation	0	uintx
MinTLABSize	Minimum allowed TLAB size (in bytes)	2*K	uintx
TLABAllocationWeight	Allocation averaging weight	35	uintx
TLABWasteTargetPercent	Percentage of Eden that can be wasted	1	uintx
TLABRefillWasteFraction	Max TLAB waste at a refill (internal fragmentation)	64	uintx
TLABWasteIncrement	Increment allowed waste at slow allocation	4	uintx
MaxLiveObjectEvacuationRatio	Max percent of eden objects that will be live at scavenge	100	uintx
OldSize	Default size of tenured generation (in bytes)	ScaleForWordSize (4096*K)	uintx
MinHeapFreeRatio	Min percentage of heap free after GC to avoid expansion	40	uintx
MaxHeapFreeRatio	Max percentage of heap free after GC to avoid shrinking	70	uintx
SoftRefLRUPolicyMSPerMB	Number of milliseconds per MB of free space in the heap	1000	intx
MinHeapDeltaBytes	Min change in heap space due to GC (in bytes)	ScaleForWordSize (128*K)	uintx
MinPermHeapExpansion	Min expansion of permanent heap (in bytes)	ScaleForWordSize (256*K)	uintx
MaxPermHeapExpansion	Max expansion of permanent heap without full GC (in bytes)	ScaleForWordSize (4*M)	uintx
QueuedAllocationWarningCount	Number of times an allocation that queues behind a GC will retry before printing a warning	0	intx
MaxTenuringThreshold	Maximum value for tenuring threshold. See more info about that flaghere.	15	intx
InitialTenuringThreshold	Initial value for tenuring threshold	7	intx
TargetSurvivorRatio	Desired percentage of survivor space used after scavenge	50	intx
MarkSweepDeadRatio	Percentage (0-100) of the old gen allowed as dead wood. "Serial mark sweep treats this as both the min and max value." CMS uses this value only if it falls back to mark sweep." Par compact uses a variable scale based on the density of the" generation and treats this as the max value when the heap is" either completely full or completely empty. Par compact also" has a smaller default value; see arguments.cpp.	5	intx
PermMarkSweepDeadRatio	Percentage (0-100) of the perm gen allowed as dead wood." See MarkSweepDeadRatio for collector-specific comments.	20	intx
MarkSweepAlwaysCompactCount	How often should we fully compact the heap (ignoring the dead space parameters)	4	intx
PrintCMSStatistics	Statistics for CMS	0	intx
PrintCMSInitiationStatistics	Statistics for initiating a CMS collection	false	bool
PrintFLSStatistics	Statistics for CMS' FreeListSpace	0	intx
PrintFLSCensus	Census for CMS' FreeListSpace	0	intx
DeferThrSuspendLoopCount	(Unstable) Number of times to iterate in safepoint loop before blocking VM threads	4000	intx
DeferPollingPageLoopCount	(Unsafe,Unstable) Number of iterations in safepoint loop before changing safepoint polling page to RO	-1	intx
SafepointSpinBeforeYield	(Unstable)	2000	intx
UseDepthFirstScavengeOrder	true: the scavenge order will be depth-first, false: the scavenge order will be breadth-first	true	bool
GCDrainStackTargetSize	how many entries we'll try to leave on the stack during parallel GC	64	uintx
ThreadSafetyMargin	Thread safety margin is used on fixed-stack LinuxThreads (on Linux/x86 only) to prevent heap-stack collision. Set to 0 to disable this feature	50*M	uintx
CodeCacheMinimumFreeSpace	When less than X space left, we stop compiling.	500*K	uintx
CompileOnly	List of methods (pkg/class.name) to restrict compilation to	""	ccstr
CompileCommandFile	Read compiler commands from this file [.hotspot_compiler]	""	ccstr
CompileCommand	Prepend to .hotspot_compiler; e.g. log,java/lang/String.	""	ccstr
CICompilerCountPerCPU	1 compiler thread for log(N CPUs)	false	bool
UseThreadPriorities	Use native thread priorities	true	bool
ThreadPriorityPolicy	0 : Normal. VM chooses priorities that are appropriate for normal applications. On Solaris NORM_PRIORITY and above are mapped to normal native priority. Java priorities below NORM_PRIORITY" map to lower native priority values. On Windows applications" are allowed to use higher native priorities. However, with ThreadPriorityPolicy=0, VM will not use the highest possible" native priority, THREAD_PRIORITY_TIME_CRITICAL, as it may interfere with system threads. On Linux thread priorities are ignored because the OS does not support static priority in SCHED_OTHER scheduling class which is the only choice for" non-root, non-realtime applications. 1 : Aggressive. Java thread priorities map over to the entire range of native thread priorities. Higher Java thread priorities map to higher native thread priorities. This policy should be used with care, as sometimes it can cause performance degradation in the application and/or the entire system. On Linux this policy requires root privilege.	0	intx
ThreadPriorityVerbose	print priority changes	false	bool
DefaultThreadPriority	what native priority threads run at if not specified elsewhere (-1 means no change)	-1	intx
CompilerThreadPriority	what priority should compiler threads run at (-1 means no change)	-1	intx
VMThreadPriority	what priority should VM threads run at (-1 means no change)	-1	intx
CompilerThreadHintNoPreempt	(Solaris only) Give compiler threads an extra quanta	true	bool
VMThreadHintNoPreempt	(Solaris only) Give VM thread an extra quanta	false	bool
JavaPriority1_To_OSPriority	Map Java priorities to OS priorities	-1	intx
JavaPriority2_To_OSPriority	Map Java priorities to OS priorities	-1	intx
JavaPriority3_To_OSPriority	Map Java priorities to OS priorities	-1	intx
JavaPriority4_To_OSPriority	Map Java priorities to OS priorities	-1	intx
JavaPriority5_To_OSPriority	Map Java priorities to OS priorities	-1	intx
JavaPriority6_To_OSPriority	Map Java priorities to OS priorities	-1	intx
JavaPriority7_To_OSPriority	Map Java priorities to OS priorities	-1	intx
JavaPriority8_To_OSPriority	Map Java priorities to OS priorities	-1	intx
JavaPriority9_To_OSPriority	Map Java priorities to OS priorities	-1	intx
JavaPriority10_To_OSPriority	Map Java priorities to OS priorities	-1	intx
StarvationMonitorInterval	Pause between each check in ms	200	intx
Tier1BytecodeLimit	Must have at least this many bytecodes before tier1" invocation counters are used	10	intx
StressTieredRuntime	Alternate client and server compiler on compile requests	false	bool
InterpreterProfilePercentage	number of method invocations/branches (expressed as % of CompileThreshold) before profiling in the interpreter	33	intx
MaxDirectMemorySize	Maximum total size of NIO direct-buffer allocations	-1	intx
UseUnsupportedDeprecatedJVMPI	Flag to temporarily re-enable the, soon to be removed, experimental interface JVMPI.	false	bool
UsePerfData	Flag to disable jvmstat instrumentation for performance testing" and problem isolation purposes.	true	bool
PerfDataSaveToFile	Save PerfData memory to hsperfdata_ file on exit	false	bool
PerfDataSamplingInterval	Data sampling interval in milliseconds	50 /*ms*/	intx
PerfDisableSharedMem	Store performance data in standard memory	false	bool
PerfDataMemorySize	Size of performance data memory region. Will be rounded up to a multiple of the native os page size.	32*K	intx
PerfMaxStringConstLength	Maximum PerfStringConstant string length before truncation	1024	intx
PerfAllowAtExitRegistration	Allow registration of atexit() methods	false	bool
PerfBypassFileSystemCheck	Bypass Win32 file system criteria checks (Windows Only)	false	bool
UnguardOnExecutionViolation	Unguard page and retry on no-execute fault (Win32 only)" 0=off, 1=conservative, 2=aggressive	0	intx
ManagementServer	Create JMX Management Server	false	bool
DisableAttachMechanism	Disable mechanism that allows tools to attach to this VM	false	bool
StartAttachListener	Always start Attach Listener at VM startup	false	bool
UseSharedSpaces	Use shared spaces in the permanent generation	true	bool
RequireSharedSpaces	Require shared spaces in the permanent generation	false	bool
ForceSharedSpaces	Require shared spaces in the permanent generation	false	bool
DumpSharedSpaces	Special mode: JVM reads a class list, loads classes, builds shared spaces, and dumps the shared spaces to a file to be used in future JVM runs.	false	bool
PrintSharedSpaces	Print usage of shared spaces	false	bool
SharedDummyBlockSize	Size of dummy block used to shift heap addresses (in bytes)	512*M	uintx
SharedReadWriteSize	Size of read-write space in permanent generation (in bytes)	12*M	uintx
SharedReadOnlySize	Size of read-only space in permanent generation (in bytes)	8*M	uintx
SharedMiscDataSize	Size of the shared data area adjacent to the heap (in bytes)	4*M	uintx
SharedMiscCodeSize	Size of the shared code area adjacent to the heap (in bytes)	4*M	uintx
TaggedStackInterpreter	Insert tags in interpreter execution stack for oopmap generaion	false	bool
ExtendedDTraceProbes	Enable performance-impacting dtrace probes	false	bool
DTraceMethodProbes	Enable dtrace probes for method-entry and method-exit	false	bool
DTraceAllocProbes	Enable dtrace probes for object allocation	false	bool
DTraceMonitorProbes	Enable dtrace probes for monitor events	false	bool
RelaxAccessControlCheck	Relax the access control checks in the verifier	false	bool
UseVMInterruptibleIO	(Unstable, Solaris-specific) Thread interrupt before or with EINTR for I/O operations results in OS_INTRPT	true	bool
AggressiveHeap	The option inspects the server resources (size of memory and number of processors), and attempts to set various parameters to be optimal for long-running, memory allocation-intensive jobs. The JVM team view AggressiveHeap as an anachronism and would like to see it go away. Instead, we'd prefer for you to determine which of the individual options that AggressiveHeap sets actually impact your app, and then set those on the command line directly. You can check the Open JDK source code to see what AggressiveHeap actually does (arguments.cpp)	false	bool
UseCompressedStrings	Use a byte[] for Strings which can be represented as pure ASCII. (Introduced in Java 6 Update 21 Performance Release)	false	bool
OptimizeStringConcat	Optimize String concatenation operations where possible. (Introduced in Java 6 Update 20)	false	bool
UseStringCache	Enables caching of commonly allocated strings.	false	bool
G1HeapRegionSize	With G1 the Java heap is subdivided into uniformly sized regions. This sets the size of the individual sub-divisions. The default value of this parameter is determined ergonomically based upon heap size. The minimum value is 1Mb and the maximum value is 32Mb. Introduced in Java 6 Update 26.	8m
G1ReservePercent	Sets the amount of heap that is reserved as a false ceiling to reduce the possibility of promotion failure. Introduced in Java 6 Update 26.	10
G1ConfidencePercent	Confidence coefficient for G1 pause prediction. Introduced in Java 6 Update 26.	50
PrintPromotionFailure	Prints additional information on GC promotion failures.		bool
manageable
HeapDumpOnOutOfMemoryError	Dump heap to file when java.lang.OutOfMemoryError is thrown	false	bool
HeapDumpPath	When HeapDumpOnOutOfMemoryError is on, the path (filename or" directory) of the dump file (defaults to java_pid.hprof" in the working directory)	""	ccstr
PrintGC	Print message at garbage collect	false	bool
PrintGCDetails	Print more details at garbage collect	false	bool
PrintGCTimeStamps	Print timestamps at garbage collect	false	bool
PrintClassHistogram	Print a histogram of class instances	false	bool
PrintConcurrentLocks	Print java.util.concurrent locks in thread dump	false	bool
experimental
UnlockExperimentalVMOptions	Unlocks experimental options.	false	bool
UseG1GC	Switch on G1 for Java6. G1 is default for Java7, so there is no such option there.	false	bool
product_rw
TraceClassLoading	Trace all classes loaded	false	bool
TraceClassUnloading	Trace unloading of classes	false	bool
TraceLoaderConstraints	Trace loader constraints	false	bool
PrintHeapAtGC	Print heap layout before and after each GC	false	bool
develop
TraceItables	Trace initialization and use of itables	false	bool
TracePcPatching	Trace usage of frame::patch_pc	false	bool
TraceJumps	Trace assembly jumps in thread ring buffer	false	bool
TraceRelocator	Trace the bytecode relocator	false	bool
TraceLongCompiles	Print out every time compilation is longer than a given threashold	false	bool
SafepointALot	Generates a lot of safepoints. Works with GuaranteedSafepointInterval	false	bool
BailoutToInterpreterForThrows	Compiled methods which throws/catches exceptions will be deopt and intp.	false	bool
NoYieldsInMicrolock	Disable yields in microlock	false	bool
TraceOopMapGeneration	Shows oopmap generation	false	bool
MethodFlushing	Reclamation of zombie and not-entrant methods	true	bool
VerifyStack	Verify stack of each thread when it is entering a runtime call	false	bool
TraceDerivedPointers	Trace traversal of derived pointers on stack	false	bool
InlineArrayCopy	inline arraycopy native that is known to be part of base library DLL	true	bool
InlineObjectHash	inline Object::hashCode() native that is known to be part of base library DLL	true	bool
InlineNatives	inline natives that are known to be part of base library DLL	true	bool
InlineMathNatives	inline SinD, CosD, etc.	true	bool
InlineClassNatives	inline Class.isInstance, etc	true	bool
InlineAtomicLong	inline sun.misc.AtomicLong	true	bool
InlineThreadNatives	inline Thread.currentThread, etc	true	bool
InlineReflectionGetCallerClass	inline sun.reflect.Reflection.getCallerClass(), known to be part of base library DLL	true	bool
InlineUnsafeOps	inline memory ops (native methods) from sun.misc.Unsafe	true	bool
ConvertCmpD2CmpF	Convert cmpD to cmpF when one input is constant in float range	true	bool
ConvertFloat2IntClipping	Convert float2int clipping idiom to integer clipping	true	bool
SpecialStringCompareTo	special version of string compareTo	true	bool
SpecialStringIndexOf	special version of string indexOf	true	bool
TraceCallFixup	traces all call fixups	false	bool
DeoptimizeALot	deoptimize at every exit from the runtime system	false	bool
DeoptimizeOnlyAt	a comma separated list of bcis to deoptimize at	""	ccstr
Debugging	set when executing debug methods in debug.ccp (to prevent triggering assertions)	false	bool
TraceHandleAllocation	Prints out warnings when suspicious many handles are allocated	false	bool
ShowSafepointMsgs	Show msg. about safepoint synch.	false	bool
SafepointTimeout	Time out and warn or fail after SafepointTimeoutDelay milliseconds if failed to reach safepoint	false	bool
DieOnSafepointTimeout	Die upon failure to reach safepoint (see SafepointTimeout)	false	bool
ForceFloatExceptions	Force exceptions on FP stack under/overflow	trueInDebug	bool
SoftMatchFailure	If the DFA fails to match a node, print a message and bail out	trueInProduct	bool
VerifyStackAtCalls	Verify that the stack pointer is unchanged after calls	false	bool
TraceJavaAssertions	Trace java language assertions	false	bool
ZapDeadCompiledLocals	Zap dead locals in compiler frames	false	bool
UseMallocOnly	use only malloc/free for allocation (no resource area/arena)	false	bool
PrintMalloc	print all malloc/free calls	false	bool
ZapResourceArea	Zap freed resource/arena space with 0xABABABAB	trueInDebug	bool
ZapJNIHandleArea	Zap freed JNI handle space with 0xFEFEFEFE	trueInDebug	bool
ZapUnusedHeapArea	Zap unused heap space with 0xBAADBABE	trueInDebug	bool
PrintVMMessages	Print vm messages on console	true	bool
Verbose	Prints additional debugging information from other modes	false	bool
PrintMiscellaneous	Prints uncategorized debugging information (requires +Verbose)	false	bool
WizardMode	Prints much more debugging information	false	bool
SegmentedHeapDumpThreshold	Generate a segmented heap dump (JAVA PROFILE 1.0.2 format) when the heap usage is larger than this	2*G	uintx
HeapDumpSegmentSize	Approximate segment size when generating a segmented heap dump	1*G	uintx
BreakAtWarning	Execute breakpoint upon encountering VM warning	false	bool
TraceVMOperation	Trace vm operations	false	bool
UseFakeTimers	Tells whether the VM should use system time or a fake timer	false	bool
PrintAssembly	Print assembly code. Requires disassembler plugin, see details here.	false	bool
PrintNMethods	Print assembly code for nmethods when generated	false	bool
PrintNativeNMethods	Print assembly code for native nmethods when generated	false	bool
PrintDebugInfo	Print debug information for all nmethods when generated	false	bool
PrintRelocations	Print relocation information for all nmethods when generated	false	bool
PrintDependencies	Print dependency information for all nmethods when generated	false	bool
PrintExceptionHandlers	Print exception handler tables for all nmethods when generated	false	bool
InterceptOSException	Starts debugger when an implicit OS (e.g., NULL) exception happens	false	bool
PrintCodeCache2	Print detailed info on the compiled_code cache when exiting	false	bool
PrintStubCode	Print generated stub code	false	bool
PrintJVMWarnings	Prints warnings for unimplemented JVM functions	false	bool
InitializeJavaLangSystem	Initialize java.lang.System - turn off for individual method debugging	true	bool
InitializeJavaLangString	Initialize java.lang.String - turn off for individual method debugging	true	bool
InitializeJavaLangExceptionsErrors	Initialize various error and exception classes - turn off for individual method debugging	true	bool
RegisterReferences	Tells whether the VM should register soft/weak/final/phantom references	true	bool
IgnoreRewrites	Supress rewrites of bytecodes in the oopmap generator. This is unsafe!	false	bool
PrintCodeCacheExtension	Print extension of code cache	false	bool
UsePrivilegedStack	Enable the security JVM functions	true	bool
IEEEPrecision	Enables IEEE precision (for INTEL only)	true	bool
ProtectionDomainVerification	Verifies protection domain before resolution in system dictionary	true	bool
DisableStartThread	Disable starting of additional Java threads (for debugging only)	false	bool
MemProfiling	Write memory usage profiling to log file	false	bool
UseDetachedThreads	Use detached threads that are recycled upon termination (for SOLARIS only)	true	bool
UsePthreads	Use pthread-based instead of libthread-based synchronization (SPARC only)	false	bool
UpdateHotSpotCompilerFileOnError	Should the system attempt to update the compiler file when an error occurs?	true	bool
LoadLineNumberTables	Tells whether the class file parser loads line number tables	true	bool
LoadLocalVariableTables	Tells whether the class file parser loads local variable tables	true	bool
LoadLocalVariableTypeTables	Tells whether the class file parser loads local variable type tables	true	bool
PreallocatedOutOfMemoryErrorCount	Number of OutOfMemoryErrors preallocated with backtrace	4	uintx
PrintBiasedLockingStatistics	Print statistics of biased locking in JVM	false	bool
TraceJVMPI	Trace JVMPI	false	bool
TraceJNICalls	Trace JNI calls	false	bool
TraceJNIHandleAllocation	Trace allocation/deallocation of JNI handle blocks	false	bool
TraceThreadEvents	Trace all thread events	false	bool
TraceBytecodes	Trace bytecode execution	false	bool
TraceClassInitialization	Trace class initialization	false	bool
TraceExceptions	Trace exceptions	false	bool
TraceICs	Trace inline cache changes	false	bool
TraceInlineCacheClearing	Trace clearing of inline caches in nmethods	false	bool
TraceDependencies	Trace dependencies	false	bool
VerifyDependencies	Exercise and verify the compilation dependency mechanism	trueInDebug	bool
TraceNewOopMapGeneration	Trace OopMapGeneration	false	bool
TraceNewOopMapGenerationDetailed	Trace OopMapGeneration: print detailed cell states	false	bool
TimeOopMap	Time calls to GenerateOopMap::compute_map() in sum	false	bool
TimeOopMap2	Time calls to GenerateOopMap::compute_map() individually	false	bool
TraceMonitorMismatch	Trace monitor matching failures during OopMapGeneration	false	bool
TraceOopMapRewrites	Trace rewritting of method oops during oop map generation	false	bool
TraceSafepoint	Trace safepoint operations	false	bool
TraceICBuffer	Trace usage of IC buffer	false	bool
TraceCompiledIC	Trace changes of compiled IC	false	bool
TraceStartupTime	Trace setup time	false	bool
TraceHPI	Trace Host Porting Interface (HPI)	false	bool
TraceProtectionDomainVerification	Trace protection domain verifcation	false	bool
TraceClearedExceptions	Prints when an exception is forcibly cleared	false	bool
UseParallelOldGCChunkPointerCalc	In the Parallel Old garbage collector use chucks to calculate" new object locations	true	bool
VerifyParallelOldWithMarkSweep	Use the MarkSweep code to verify phases of Parallel Old	false	bool
VerifyParallelOldWithMarkSweepInterval	Interval at which the MarkSweep code is used to verify phases of Parallel Old	1	uintx
ParallelOldMTUnsafeMarkBitMap	Use the Parallel Old MT unsafe in marking the bitmap	false	bool
ParallelOldMTUnsafeUpdateLiveData	Use the Parallel Old MT unsafe in update of live size	false	bool
TraceChunkTasksQueuing	Trace the queuing of the chunk tasks	false	bool
ScavengeWithObjectsInToSpace	Allow scavenges to occur when to_space contains objects.	false	bool
UseCMSAdaptiveFreeLists	Use Adaptive Free Lists in the CMS generation	true	bool
UseAsyncConcMarkSweepGC	Use Asynchronous Concurrent Mark-Sweep GC in the old generation	true	bool
RotateCMSCollectionTypes	Rotate the CMS collections among concurrent and STW	false	bool
CMSTraceIncrementalMode	Trace CMS incremental mode	false	bool
CMSTraceIncrementalPacing	Trace CMS incremental mode pacing computation	false	bool
CMSTraceThreadState	Trace the CMS thread state (enable the trace_state() method)	false	bool
CMSDictionaryChoice	Use BinaryTreeDictionary as default in the CMS generation	0	intx
CMSOverflowEarlyRestoration	Whether preserved marks should be restored early	false	bool
CMSTraceSweeper	Trace some actions of the CMS sweeper	false	bool
FLSVerifyDictionary	Do lots of (expensive) FLS dictionary verification	false	bool
VerifyBlockOffsetArray	Do (expensive!) block offset array verification	false	bool
TraceCMSState	Trace the state of the CMS collection	false	bool
CMSTestInFreeList	Check if the coalesced range is already in the free lists as claimed.	false	bool
CMSIgnoreResurrection	Ignore object resurrection during the verification.	true	bool
FullGCALot	Force full gc at every Nth exit from the runtime system (N=FullGCALotInterval)	false	bool
PromotionFailureALotCount	Number of promotion failures occurring at ParGCAllocBuffer" refill attempts (ParNew) or promotion attempts (other young collectors)	1000	uintx
PromotionFailureALotInterval	Total collections between promotion failures alot	5	uintx
WorkStealingSleepMillis	Sleep time when sleep is used for yields	1	intx
WorkStealingYieldsBeforeSleep	Number of yields before a sleep is done during workstealing	1000	uintx
TraceAdaptiveGCBoundary	Trace young-old boundary moves	false	bool
PSAdaptiveSizePolicyResizeVirtualSpaceAlot	Resize the virtual spaces of the young or old generations	-1	intx
PSAdjustTenuredGenForMinorPause	Adjust tenured generation to achive a minor pause goal	false	bool
PSAdjustYoungGenForMajorPause	Adjust young generation to achive a major pause goal	false	bool
AdaptiveSizePolicyReadyThreshold	Number of collections before the adaptive sizing is started	5	uintx
AdaptiveSizePolicyGCTimeLimitThreshold	Number of consecutive collections before gc time limit fires	5	uintx
UsePrefetchQueue	Use the prefetch queue during PS promotion	true	bool
ConcGCYieldTimeout	If non-zero, assert that GC threads yield within this # of ms.	0	intx
TraceReferenceGC	Trace handling of soft/weak/final/phantom references	false	bool
TraceFinalizerRegistration	Trace registration of final references	false	bool
TraceWorkGang	Trace activities of work gangs	false	bool
TraceBlockOffsetTable	Print BlockOffsetTable maps	false	bool
TraceCardTableModRefBS	Print CardTableModRefBS maps	false	bool
TraceGCTaskManager	Trace actions of the GC task manager	false	bool
TraceGCTaskQueue	Trace actions of the GC task queues	false	bool
TraceGCTaskThread	Trace actions of the GC task threads	false	bool
TraceParallelOldGCMarkingPhase	Trace parallel old gc marking phase	false	bool
TraceParallelOldGCSummaryPhase	Trace parallel old gc summary phase	false	bool
TraceParallelOldGCCompactionPhase	Trace parallel old gc compaction phase	false	bool
TraceParallelOldGCDensePrefix	Trace parallel old gc dense prefix computation	false	bool
IgnoreLibthreadGPFault	Suppress workaround for libthread GP fault	false	bool
CIPrintCompilerName	when CIPrint is active, print the name of the active compiler	false	bool
CIPrintCompileQueue	display the contents of the compile queue whenever a compilation is enqueued	false	bool
CIPrintRequests	display every request for compilation	false	bool
CITimeEach	display timing information after each successful compilation	false	bool
CICountOSR	use a separate counter when assigning ids to osr compilations	true	bool
CICompileNatives	compile native methods if supported by the compiler	true	bool
CIPrintMethodCodes	print method bytecodes of the compiled code	false	bool
CIPrintTypeFlow	print the results of ciTypeFlow analysis	false	bool
CITraceTypeFlow	detailed per-bytecode tracing of ciTypeFlow analysis	false	bool
CICloneLoopTestLimit	size limit for blocks heuristically cloned in ciTypeFlow	100	intx
UseStackBanging	use stack banging for stack overflow checks (required for proper StackOverflow handling; disable only to measure cost of stackbanging)	true	bool
Use24BitFPMode	Set 24-bit FPU mode on a per-compile basis	true	bool
Use24BitFP	use FP instructions that produce 24-bit precise results	true	bool
UseStrictFP	use strict fp if modifier strictfp is set	true	bool
GenerateSynchronizationCode	generate locking/unlocking code for synchronized methods and monitors	true	bool
GenerateCompilerNullChecks	Generate explicit null checks for loads/stores/calls	true	bool
GenerateRangeChecks	Generate range checks for array accesses	true	bool
PrintSafepointStatistics	print statistics about safepoint synchronization	false	bool
InlineAccessors	inline accessor methods (get/set)	true	bool
UseCHA	enable CHA	true	bool
PrintInlining	prints inlining optimizations	false	bool
EagerInitialization	Eagerly initialize classes if possible	false	bool
TraceMethodReplacement	Print when methods are replaced do to recompilation	false	bool
PrintMethodFlushing	print the nmethods being flushed	false	bool
UseRelocIndex	use an index to speed random access to relocations	false	bool
StressCodeBuffers	Exercise code buffer expansion and other rare state changes	false	bool
DebugVtables	add debugging code to vtable dispatch	false	bool
PrintVtables	print vtables when printing klass	false	bool
TraceCreateZombies	trace creation of zombie nmethods	false	bool
MonomorphicArrayCheck	Uncommon-trap array store checks that require full type check	true	bool
DelayCompilationDuringStartup	Delay invoking the compiler until main application class is loaded	true	bool
CompileTheWorld	Compile all methods in all classes in bootstrap class path (stress test)	false	bool
CompileTheWorldPreloadClasses	Preload all classes used by a class before start loading	true	bool
TraceIterativeGVN	Print progress during Iterative Global Value Numbering	false	bool
FillDelaySlots	Fill delay slots (on SPARC only)	true	bool
VerifyIterativeGVN	Verify Def-Use modifications during sparse Iterative Global Value Numbering	false	bool
TimeLivenessAnalysis	Time computation of bytecode liveness analysis	false	bool
TraceLivenessGen	Trace the generation of liveness analysis information	false	bool
PrintDominators	Print out dominator trees for GVN	false	bool
UseLoopSafepoints	Generate Safepoint nodes in every loop	true	bool
DeutschShiffmanExceptions	Fast check to find exception handler for precisely typed exceptions	true	bool
FastAllocateSizeLimit	Inline allocations larger than this in doublewords must go slow	100000	intx
UseVTune	enable support for Intel's VTune profiler	false	bool
CountCompiledCalls	counts method invocations	false	bool
CountJNICalls	counts jni method invocations	false	bool
ClearInterpreterLocals	Always clear local variables of interpreter activations upon entry	false	bool
UseFastSignatureHandlers	Use fast signature handlers for native calls	true	bool
UseV8InstrsOnly	Use SPARC-V8 Compliant instruction subset	false	bool
UseCASForSwap	Do not use swap instructions, but only CAS (in a loop) on SPARC	false	bool
PoisonOSREntry	Detect abnormal calls to OSR code	true	bool
CountBytecodes	Count number of bytecodes executed	false	bool
PrintBytecodeHistogram	Print histogram of the executed bytecodes	false	bool
PrintBytecodePairHistogram	Print histogram of the executed bytecode pairs	false	bool
PrintSignatureHandlers	Print code generated for native method signature handlers	false	bool
VerifyOops	Do plausibility checks for oops	false	bool
CheckUnhandledOops	Check for unhandled oops in VM code	false	bool
VerifyJNIFields	Verify jfieldIDs for instance fields	trueInDebug	bool
VerifyFPU	Verify FPU state (check for NaN's, etc.)	false	bool
VerifyThread	Watch the thread register for corruption (SPARC only)	false	bool
VerifyActivationFrameSize	Verify that activation frame didn't become smaller than its minimal size	false	bool
TraceFrequencyInlining	Trace frequency based inlining	false	bool
PrintMethodData	Print the results of +ProfileInterpreter at end of run	false	bool
VerifyDataPointer	Verify the method data pointer during interpreter profiling	trueInDebug	bool
TraceCompilationPolicy	Trace compilation policy	false	bool
TimeCompilationPolicy	Time the compilation policy	false	bool
CounterHalfLifeTime	half-life time of invocation counters (in secs)	30	intx
CounterDecayMinIntervalLength	Min. ms. between invocation of CounterDecay	500	intx
TraceDeoptimization	Trace deoptimization	false	bool
DebugDeoptimization	Tracing various information while debugging deoptimization	false	bool
GuaranteedSafepointInterval	Guarantee a safepoint (at least) every so many milliseconds (0 means none)	1000	intx
SafepointTimeoutDelay	Delay in milliseconds for option SafepointTimeout	10000	intx
MallocCatchPtr	Hit breakpoint when mallocing/freeing this pointer	-1	intx
TotalHandleAllocationLimit	Threshold for total handle allocation when +TraceHandleAllocation is used	1024	uintx
StackPrintLimit	number of stack frames to print in VM-level stack dump	100	intx
MaxInlineLevel	maximum number of nested calls that are inlined	9	intx
MaxRecursiveInlineLevel	maximum number of nested recursive calls that are inlined	1	intx
InlineSmallCode	Only inline already compiled methods if their code size is less than this	1000	intx
MaxTrivialSize	maximum bytecode size of a trivial method to be inlined	6	intx
MinInliningThreshold	min. invocation count a method needs to have to be inlined	250	intx
AlignEntryCode	aligns entry code to specified value (in bytes)	4	intx
MethodHistogramCutoff	cutoff value for method invoc. histogram (+CountCalls)	100	intx
ProfilerNumberOfInterpretedMethods	# of interpreted methods to show in profile	25	intx
ProfilerNumberOfCompiledMethods	# of compiled methods to show in profile	25	intx
ProfilerNumberOfStubMethods	# of stub methods to show in profile	25	intx
ProfilerNumberOfRuntimeStubNodes	# of runtime stub nodes to show in profile	25	intx
DontYieldALotInterval	Interval between which yields will be dropped (milliseconds)	10	intx
MinSleepInterval	Minimum sleep() interval (milliseconds) when ConvertSleepToYield is off (used for SOLARIS)	1	intx
ProfilerPCTickThreshold	Number of ticks in a PC buckets to be a hotspot	15	intx
StressNonEntrant	Mark nmethods non-entrant at registration	false	bool
TypeProfileWidth	number of receiver types to record in call profile	2	intx
BciProfileWidth	number of return bci's to record in ret profile	2	intx
FreqCountInvocations	Scaling factor for branch frequencies (deprecated)	1	intx
InlineFrequencyRatio	Ratio of call site execution to caller method invocation	20	intx
InlineThrowCount	Force inlining of interpreted methods that throw this often	50	intx
InlineThrowMaxSize	Force inlining of throwing methods smaller than this	200	intx
VerifyAliases	perform extra checks on the results of alias analysis	false	bool
ProfilerNodeSize	Size in K to allocate for the Profile Nodes of each thread	1024	intx
V8AtomicOperationUnderLockSpinCount	Number of times to spin wait on a v8 atomic operation lock	50	intx
ExitAfterGCNum	If non-zero, exit after this GC.	0	uintx
GCExpandToAllocateDelayMillis	Delay in ms between expansion and allocation	0	uintx
CodeCacheSegmentSize	Code cache segment size (in bytes) - smallest unit of allocation	64	uintx
BinarySwitchThreshold	Minimal number of lookupswitch entries for rewriting to binary switch	5	intx
StopInterpreterAt	Stops interpreter execution at specified bytecode number	0	intx
TraceBytecodesAt	Traces bytecodes starting with specified bytecode number	0	intx
CIStart	the id of the first compilation to permit	0	intx
CIStop	the id of the last compilation to permit	-1	intx
CIStartOSR	the id of the first osr compilation to permit (CICountOSR must be on)	0	intx
CIStopOSR	the id of the last osr compilation to permit (CICountOSR must be on)	-1	intx
CIBreakAtOSR	id of osr compilation to break at	-1	intx
CIBreakAt	id of compilation to break at	-1	intx
CIFireOOMAt	Fire OutOfMemoryErrors throughout CI for testing the compiler (non-negative value throws OOM after this many CI accesses in each compile)	-1	intx
CIFireOOMAtDelay	Wait for this many CI accesses to occur in all compiles before beginning to throw OutOfMemoryErrors in each compile	-1	intx
NewCodeParameter	Testing Only: Create a dedicated integer parameter before putback	0	intx
MinOopMapAllocation	Minimum number of OopMap entries in an OopMapSet	8	intx
LongCompileThreshold	Used with +TraceLongCompiles	50	intx
MaxRecompilationSearchLength	max. # frames to inspect searching for recompilee	10	intx
MaxInterpretedSearchLength	max. # interp. frames to skip when searching for recompilee	3	intx
DesiredMethodLimit	desired max. method size (in bytecodes) after inlining	8000	intx
HugeMethodLimit	don't compile methods larger than this if +DontCompileHugeMethods	8000	intx
UseNewReflection	Temporary flag for transition to reflection based on dynamic bytecode generation in 1.4; can no longer be turned off in 1.4 JDK, and is unneeded in 1.3 JDK, but marks most places VM changes were needed	true	bool
VerifyReflectionBytecodes	Force verification of 1.4 reflection bytecodes. Does not work in situations like that described in 4486457 or for constructors generated for serialization, so can not be enabled in product.	false	bool
FastSuperclassLimit	Depth of hardwired instanceof accelerator array	8	intx
PerfTraceDataCreation	Trace creation of Performance Data Entries	false	bool
PerfTraceMemOps	Trace PerfMemory create/attach/detach calls	false	bool
SharedOptimizeColdStartPolicy	Reordering policy for SharedOptimizeColdStart 0=favor classload-time locality, 1=balanced, 2=favor runtime locality	2	intx
product_pd
UseLargePages	Use large page memory		bool
UseSSE	0=fpu stack,1=SSE for floats,2=SSE/SSE2 for all (x86/amd only)		intx
UseISM	Use Intimate Shared Memory. [Not accepted for non-Solaris platforms.] For details, see Intimate Shared Memory.	true	bool
UseMPSS	Use Multiple Page Size Support w/4mb pages for the heap. Do not use with ISM as this replaces the need for ISM. (Introduced in 1.4.0 update 1, Relevant to Solaris 9 and newer.) [1.4.1 and earlier: false]	false	bool
BackgroundCompilation	A thread requesting compilation is not blocked during compilation		bool
UseVectoredExceptions	Temp Flag - Use Vectored Exceptions rather than SEH (Windows Only)		bool
DontYieldALot	Throw away obvious excess yield calls (for SOLARIS only)		bool
ConvertSleepToYield	Converts sleep(0) to thread yield (may be off for SOLARIS to improve GUI)		bool
UseTLAB	Use thread-local object allocation		bool
ResizeTLAB	Dynamically resize tlab size for threads		bool
NeverActAsServerClassMachine	Never act like a server-class machine		bool
PrefetchCopyIntervalInBytes	How far ahead to prefetch destination area (<= 0 means off)		intx
PrefetchScanIntervalInBytes	How far ahead to prefetch scan area (<= 0 means off)		intx
PrefetchFieldsAhead	How many fields ahead to prefetch in oop scan (<= 0 means off)		intx
CompilationPolicyChoice	which compilation policy		intx
RewriteBytecodes	Allow rewriting of bytecodes (bytecodes are not immutable)		bool
RewriteFrequentPairs	Rewrite frequently used bytecode pairs into a single bytecode		bool
UseOnStackReplacement	Use on stack replacement, calls runtime if invoc. counter overflows in loop		bool
PreferInterpreterNativeStubs	Use always interpreter stubs for native methods invoked via interpreter		bool
AllocatePrefetchStyle	0=no prefetch, 1=dead load, 2=prefetch instruction		intx
AllocatePrefetchDistance	Distance to prefetch ahead of allocation pointer		intx
FreqInlineSize	maximum bytecode size of a frequent method to be inlined		intx
PreInflateSpin	Number of times to spin wait before inflation		intx
NewSize	Default size of new generation (in bytes)		uintx
TLABSize	Default (or starting) size of TLAB (in bytes)		uintx
SurvivorRatio	Ratio of eden/survivor space size		intx
NewRatio	Ratio of new/old generation sizes		intx
NewSizeThreadIncrease	Additional size added to desired new generation size per non-daemon thread (in bytes)		uintx
PermSize	Default size of permanent generation (in bytes)		uintx
MaxPermSize	Maximum size of permanent generation (in bytes)		uintx
StackYellowPages	Number of yellow zone (recoverable overflows) pages		intx
StackRedPages	Number of red zone (unrecoverable overflows) pages		intx
StackShadowPages	Number of shadow zone (for overflow checking) pages this should exceed the depth of the VM and native call stack. In the HotSpot implementation, Java methods share stack frames with C/C++ native code, namely user native code and the virtual machine itself. Java methods generate code that checks that stack space is available a fixed distance towards the end of the stack so that the native code can be called without exceeding the stack space. This distance towards the end of the stack is called “Shadow Pages”. The page size usually is 4096b, which mean that 20 pages would occupy 90Kb. See some more info on that parameter in bug 7059899 and Crash due to Stack Overflow section of "Troubleshooting System Crashes" from Oracle.	Depends on machine. It's 3 on x86, 6 on amd64, etc	intx
ThreadStackSize	Thread Stack Size (in Kbytes)		intx
VMThreadStackSize	Non-Java Thread Stack Size (in Kbytes)		intx
CompilerThreadStackSize	Compiler Thread Stack Size (in Kbytes)		intx
InitialCodeCacheSize	Initial code cache size (in bytes)		uintx
ReservedCodeCacheSize	Reserved code cache size (in bytes) - maximum code cache size		uintx
CodeCacheExpansionSize	Code cache expansion size (in bytes)		uintx
CompileThreshold	number of method invocations/branches before (re-)compiling	10000	intx
Tier2CompileThreshold	threshold at which a tier 2 compilation is invoked		intx
Tier2BackEdgeThreshold	Back edge threshold at which a tier 2 compilation is invoked		intx
TieredCompilation	Enable two-tier compilation		bool
OnStackReplacePercentage	number of method invocations/branches (expressed as % of CompileThreshold) before (re-)compiling OSR code		intx
develop_pd
ShareVtableStubs	Share vtable stubs (smaller code but worse branch prediction		bool
CICompileOSR	compile on stack replacement methods if supported by the compiler		bool
ImplicitNullChecks	generate code for implicit null checks		bool
UncommonNullCast	Uncommon-trap NULLs passed to check cast		bool
InlineIntrinsics	Inline intrinsics that can be statically resolved		bool
ProfileInterpreter	Profile at the bytecode level during interpretation		bool
ProfileTraps	Profile deoptimization traps at the bytecode level		bool
InlineFrequencyCount	Count of call site execution necessary to trigger frequent inlining		intx
JVMInvokeMethodSlack	Stack space (bytes) required for JVM_InvokeMethod to complete		uintx
CodeEntryAlignment	Code entry alignment for generated code (in bytes)		intx
CodeCacheMinBlockLength	Minimum number of segments in a code cache block.		uintx
notproduct
StressDerivedPointers	Force scavenge when a derived pointers is detected on stack after rtm call	false	bool
TraceCodeBlobStacks	Trace stack-walk of codeblobs	false	bool
PrintRewrites	Print methods that are being rewritten	false	bool
DeoptimizeRandom	deoptimize random frames on random exit from the runtime system	false	bool
ZombieALot	creates zombies (non-entrant) at exit from the runt. system	false	bool
WalkStackALot	trace stack (no print) at every exit from the runtime system	false	bool
StrictSafepointChecks	Enable strict checks that safepoints cannot happen for threads that used No_Safepoint_Verifier	trueInDebug	bool
VerifyLastFrame	Verify oops on last frame on entry to VM	false	bool
LogEvents	Enable Event log	trueInDebug	bool
CheckAssertionStatusDirectives	temporary - see javaClasses.cpp	false	bool
PrintMallocFree	Trace calls to C heap malloc/free allocation	false	bool
PrintOopAddress	Always print the location of the oop	false	bool
VerifyCodeCacheOften	Verify compiled-code cache often	false	bool
ZapDeadLocalsOld	Zap dead locals (old version, zaps all frames when entering the VM	false	bool
CheckOopishValues	Warn if value contains oop ( requires ZapDeadLocals)	false	bool
ZapVMHandleArea	Zap freed VM handle space with 0xBCBCBCBC	trueInDebug	bool
PrintCompilation2	Print additional statistics per compilation	false	bool
PrintAdapterHandlers	Print code generated for i2c/c2i adapters	false	bool
PrintCodeCache	Print the compiled_code cache when exiting	false	bool
ProfilerCheckIntervals	Collect and print info on spacing of profiler ticks	false	bool
WarnOnStalledSpinLock	Prints warnings for stalled SpinLocks	0	uintx
PrintSystemDictionaryAtExit	Prints the system dictionary at exit	false	bool
ValidateMarkSweep	Do extra validation during MarkSweep collection	false	bool
RecordMarkSweepCompaction	Enable GC-to-GC recording and querying of compaction during MarkSweep	false	bool
TraceRuntimeCalls	Trace run-time calls	false	bool
TraceJVMCalls	Trace JVM calls	false	bool
TraceInvocationCounterOverflow	Trace method invocation counter overflow	false	bool
TraceZapDeadLocals	Trace zapping dead locals	false	bool
CMSMarkStackOverflowALot	Whether we should simulate frequent marking stack / work queue" overflow	false	bool
CMSMarkStackOverflowInterval	A per-thread `interval' counter that determines how frequently" we simulate overflow; a smaller number increases frequency	1000	intx
CMSVerifyReturnedBytes	Check that all the garbage collected was returned to the free lists.	false	bool
ScavengeALot	Force scavenge at every Nth exit from the runtime system (N=ScavengeALotInterval)	false	bool
GCALotAtAllSafepoints	Enforce ScavengeALot/GCALot at all potential safepoints	false	bool
PromotionFailureALot	Use promotion failure handling on every youngest generation collection	false	bool
CheckMemoryInitialization	Checks memory initialization	false	bool
TraceMarkSweep	Trace mark sweep	false	bool
PrintReferenceGC	Print times spent handling reference objects during GC (enabled only when PrintGCDetails)	false	bool
TraceScavenge	Trace scavenge	false	bool
TimeCompiler	time the compiler	false	bool
TimeCompiler2	detailed time the compiler (requires +TimeCompiler)	false	bool
LogMultipleMutexLocking	log locking and unlocking of mutexes (only if multiple locks are held)	false	bool
PrintSymbolTableSizeHistogram	print histogram of the symbol table	false	bool
ExitVMOnVerifyError	standard exit from VM if bytecode verify error (only in debug mode)	false	bool
AbortVMOnException	Call fatal if this exception is thrown. Example: java -XX:AbortVMOnException=java.lang.NullPointerException Foo	""	ccstr
PrintVtableStats	print vtables stats at end of run	false	bool
IgnoreLockingAssertions	disable locking assertions (for speed)	false	bool
VerifyLoopOptimizations	verify major loop optimizations	false	bool
CompileTheWorldIgnoreInitErrors	Compile all methods although class initializer failed	false	bool
TracePhaseCCP	Print progress during Conditional Constant Propagation	false	bool
TraceLivenessQuery	Trace queries of liveness analysis information	false	bool
CollectIndexSetStatistics	Collect information about IndexSets	false	bool
TraceCISCSpill	Trace allocators use of cisc spillable instructions	false	bool
TraceSpilling	Trace spilling	false	bool
CountVMLocks	counts VM internal lock attempts and contention	false	bool
CountRuntimeCalls	counts VM runtime calls	false	bool
CountJVMCalls	counts jvm method invocations	false	bool
CountRemovableExceptions	count exceptions that could be replaced by branches due to inlining	false	bool
ICMissHistogram	produce histogram of IC misses	false	bool
PrintClassStatistics	prints class statistics at end of run	false	bool
PrintMethodStatistics	prints method statistics at end of run	false	bool
TraceOnStackReplacement	Trace on stack replacement	false	bool
VerifyJNIEnvThread	Verify JNIEnv.thread == Thread::current() when entering VM from JNI	false	bool
TraceTypeProfile	Trace type profile	false	bool
MemProfilingInterval	Time between each invocation of the MemProfiler	500	intx
AssertRepeat	number of times to evaluate expression in assert (to estimate overhead); only works with -DUSE_REPEATED_ASSERTS	1	intx
SuppressErrorAt	List of assertions (file:line) to muzzle	""	ccstr
HandleAllocationLimit	Threshold for HandleMark allocation when +TraceHandleAllocation is used	1024	uintx
MaxElementPrintSize	maximum number of elements to print	256	intx
MaxSubklassPrintSize	maximum number of subklasses to print when printing klass	4	intx
ScavengeALotInterval	Interval between which scavenge will occur with +ScavengeALot	1	intx
FullGCALotInterval	Interval between which full gc will occur with +FullGCALot	1	intx
FullGCALotStart	For which invocation to start FullGCAlot	0	intx
FullGCALotDummies	Dummy object allocated with +FullGCALot, forcing all objects to move	32*K	intx
DeoptimizeALotInterval	Number of exits until DeoptimizeALot kicks in	5	intx
ZombieALotInterval	Number of exits until ZombieALot kicks in	5	intx
ExitOnFullCodeCache	Exit the VM if we fill the code cache.	false	bool
CompileTheWorldStartAt	First class to consider when using +CompileTheWorld	1	intx
CompileTheWorldStopAt	Last class to consider when using +CompileTheWorld	max_jint	intx
diagnostic
PrintFlagsFinal	Prints list of all available java paramenters. Information is displayed in 4 columns. First one is the type of parameter, second is parameter name, third is default value and the fourth is the type of the flag, i.e. product, diagnostic, C1 product (only for client JVM), C2 product (only for server JVM), etc. Available since 1.6.
UnlockDiagnosticVMOptions	Enable processing of flags relating to field diagnostics	trueInDebug	bool
LogCompilation	Log compilation activity in detail to hotspot.log or LogFile	false	bool
UnsyncloadClass	Unstable: VM calls loadClass unsynchronized. Custom classloader must call VM synchronized for findClass & defineClass	false	bool
FLSVerifyAllHeapReferences	Verify that all refs across the FLS boundary are to valid objects	false	bool
FLSVerifyLists	Do lots of (expensive) FreeListSpace verification	false	bool
FLSVerifyIndexTable	Do lots of (expensive) FLS index table verification	false	bool
VerifyBeforeExit	Verify system before exiting	trueInDebug	bool
VerifyBeforeGC	Verify memory system before GC	false	bool
VerifyAfterGC	Verify memory system after GC	false	bool
VerifyDuringGC	Verify memory system during GC (between phases)	false	bool
VerifyRememberedSets	Verify GC remembered sets	false	bool
VerifyObjectStartArray	Verify GC object start array if verify before/after	true	bool
BindCMSThreadToCPU	Bind CMS Thread to CPU if possible	false	bool
CPUForCMSThread	When BindCMSThreadToCPU is true, the CPU to bind CMS thread to	0	uintx
TraceJVMTIObjectTagging	Trace JVMTI object tagging calls	false	bool
VerifyBeforeIteration	Verify memory system before JVMTI iteration	false	bool
DebugNonSafepoints	Generate extra debugging info for non-safepoints in nmethods	trueInDebug	bool
SerializeVMOutput	Use a mutex to serialize output to tty and hotspot.log	true	bool
DisplayVMOutput	Display all VM output on the tty, independently of LogVMOutput	true	bool
LogVMOutput	Save VM output to hotspot.log, or to LogFile	trueInDebug	bool
LogFile	If LogVMOutput is on, save VM output to this file [hotspot.log]	""	ccstr
MallocVerifyInterval	if non-zero, verify C heap after every N calls to malloc/realloc/free	0	intx
MallocVerifyStart	if non-zero, start verifying C heap after Nth call to malloc/realloc/free	0	intx
VerifyGCStartAt	GC invoke count where +VerifyBefore/AfterGC kicks in	0	uintx
VerifyGCLevel	Generation level at which to start +VerifyBefore/AfterGC	0	intx
UseNewCode	Testing Only: Use the new version while testing	false	bool
UseNewCode2	Testing Only: Use the new version while testing	false	bool
UseNewCode3	Testing Only: Use the new version while testing	false	bool
SharedOptimizeColdStart	At dump time, order shared objects to achieve better cold startup time.	true	bool
SharedSkipVerify	Skip assert() and verify() which page-in unwanted shared objects.	false	bool
PauseAtStartup	Causes the VM to pause at startup time and wait for the pause file to be removed (default: ./vm.paused.)	false	bool
PauseAtStartupFile	The file to create and for whose removal to await when pausing at startup. (default: ./vm.paused.)	""	ccstr

-X:

-Xbootclasspath
-Xbootclasspath/a
-Xbootclasspath/p
-Xcheck:jni
-XclearType
-Xdebug
-Xgc
-XgcPause
-XgcPrio
-XgcReport
-XlargePages
-Xmanagement
-Xms
-Xmx
-XnoClassGC
-Xnohup
-XnoOpt
-Xns
-XpauseTarget
-Xrs
-Xrunjdwp
-Xss
-XstrictFP
-Xverbose
-XverboseDecorations
-XverboseLog
-XverboseTimeStamp
-Xverify

For more details : http://docs.oracle.com/cd/E13150_01/jrockit_jvm/jrockit/jrdocs/refman/optionX.html

Some important parameters:

-Xms

The -Xms option sets the initial and minimum Java heap size. The Java heap (the “heap”) is the part of the memory where blocks of memory are allocated to objects and freed during garbage collection.

Note:

-Xms does not limit the total amount of memory that the JVM can use.

Operation

Format: -Xms[g|G|m|M|k|K]

Combine -Xms with a memory value and add a unit.

For Example:

java -Xms:64m myApp

sets the initial and minimum java heap to 64 MB.

If you do not add a unit, you will get the exact value you state; for example, 64 will be interpreted as 64 bytes, not 64 megabytes or 64 kilobytes.

For best performance, set -Xms to the same size as the maximum heap size, for example:

java -Xgcprio:throughput -Xmx:64m -Xms:64m myApp

Default Values

If you do not set this, the minimum Java heap size defaults to (depending on which mode you are running):

•  -server mode: 25% of the amount of free physical memory in the system, up to 64 MB and at least 8 MB
•  -client mode: 25% of the amount of free physical memory in the system, up to 16 MB and at least 8 MB
•  If the nursery size is set with -Xns, the default initial heap size will be scaled up to at least twice the nursery size.

Flags or Other Options Affected

None

Exceptions and Recommendations

The initial Java heap cannot be set to a smaller value than 8 MB, which is the minimum Java heap size. If you attempt to set it to a smaller value, JRockit JVM defaults to 8 MB.

The -Xms value cannot exceed the value set for -Xmx (the maximum Java heap size).

-Xmx

This option sets the maximum Java heap size. The Java heap (the “heap”) is the part of the memory where blocks of memory are allocated to objects and freed during garbage collection. Depending upon the kind of operating system you are running, the maximum value you can set for the Java heap can vary.

Note:

-Xmx does not limit the total amount of memory that the JVM can use.

Operation

Format: -Xmx[g|G|m|M|k|K]

Combine -Xmx with a memory value

For Example:

java -Xmx:1g myApp

sets the maximum java heap to 1 gigabyte.

If you do not add a unit, you will get the exact value you state; for example, 64 will be interpreted as 64 bytes, not 64 megabytes or 64 kilobytes.

The -Xmx option and -Xms option in combination are used to limit the Java heap size. The Java heap can never grow larger than -Xmx. Also, the -Xms value can be used as “minimum heap size” to set a fixed heap size by setting -Xms = -Xmx when, for example, you want to run benchmark tests.

Known Issue for Linux Users

The JRockit JVM R26.0.0 on Linux IA32 can experience problems setting up memory for object allocation. When this happens, you will receive the following message:

[JRockit] ERROR: Fatal error in JRockit during memory setup phase. 
Try to reduce the heap size using -Xmx:m, i.e. “-Xmx:16m”. Could 
not create the Java virtual machine.

and JRockit JVM will be exited.

The workaround for this situation is to try different -Xmx values until you find a heap size that is setup correct.

Note:

This known issue is valid for R26.0.0.

Default Value

If you do not set this, the maximum java heap size depends on the platform and the amount of memory in the system as described in Table 2-6.

Table 2-6 Default Maximum Heap Sizes

Release	Platform	Default Maximum Heap Size
R27.2 and older	Windows	75% of total physical memory up to 1 GB
R27.2 and older	Linux, Solaris	50% of available physical memory up to 1 GB
R27.3 and newer	Windows on a 64 bit platform	75% of total physical memory up to 2 GB
R27.3 and newer	Linux or Solaris on a 64 bit platform	50% of available physical memory up to 2 GB
R72.3 and newer	Windows on a 32 bit platform	75% of total physical memory up to 1 GB
R27.3 and newer	Linux on a 32 bit platform	50% of available physical memory up to 1 GB

Flags or Other Options Affected

None.

Exceptions

When using-Xmx, be aware of the following exceptions:

•  If both -Xmx and -Xms are specified the value of -Xmx must be larger than or equal to that of -Xms.
•  If both -Xmx and -Xns are specified the value of -Xmx must be larger than or equal to that of -Xns.
•  The minimum value for -Xmx is 16 MB.

-Xmn

the size of the heap for the young generation

-Xss

-Xss sets the thread stack size. Thread stacks are memory areas allocated for each Java thread for their internal use. This is where the thread stores its local execution state.

Operation

Format: -Xss[g|G|m|M|k|K]

Combine -Xss with a memory value

For Example:

java -Xss:512k myApp

sets the default stack size to 512 kilobytes.

If you do not add a unit, you will get the exact value you state; for example, 64 will be 64 bytes, not 64 megabytes or 64 kilobytes.

Default Value

-Xss default values are platform-specific, as defined in Table 2-9.

Table 2-9 -Xss Default Values

Platform	Default
Windows IA32	64 KB
Linux IA32	128 KB
Windows x86_64	128 KB
Linux x86_64	256 KB
Windows IA64	320 KB
Linux IA64	1024 KB (1 MB)
Solaris Sparc	512 KB

Flags or Other Options Affected

None

Exceptions

None