如何查看jvm中的各种参数以及默认值

1 标准参数
标准参数（-），所有的JVM实现都必须实现这些参数的功能，而且向后兼容；
通过命令 java即可查看
如下

where options include:
-d32 use a 32-bit data model if available
-d64 use a 64-bit data model if available
-server to select the "server" VM
The default VM is server,
because you are running on a server-class machine.

-cp 
-classpath 
              A : separated list of directories, JAR archives,
              and ZIP archives to search for class files.
-D=
              set a system property
-verbose:[class|gc|jni]
              enable verbose output
-version      print product version and exit

2 非标准参数（-X）
非标准参数（-X），默认jvm实现这些参数的功能，但是并不保证所有jvm实现都满足，且不保证向后兼容；
通过命令 java -X，如下

-Xmixed           mixed mode execution (default)
-Xint             interpreted mode execution only
-Xbootclasspath:
                  set search path for bootstrap classes and resources
-Xbootclasspath/a:
                  append to end of bootstrap class path
-Xbootclasspath/p:
                  prepend in front of bootstrap class path
-Xdiag            show additional diagnostic messages
-Xnoclassgc       disable class garbage collection
-Xincgc           enable incremental garbage collection
-Xloggc:    log GC status to a file with time stamps
-Xbatch           disable background compilation
-Xms        set initial Java heap size
-Xmx        set maximum Java heap size
-Xss        set java thread stack size
-Xprof            output cpu profiling data
-Xfuture          enable strictest checks, anticipating future default
-Xrs              reduce use of OS signals by Java/VM (see documentation)
-Xcheck:jni       perform additional checks for JNI functions
-Xshare:off       do not attempt to use shared class data
-Xshare:auto      use shared class data if possible (default)
-Xshare:on        require using shared class data, otherwise fail.
-XshowSettings    show all settings and continue
-XshowSettings:all
                  show all settings and continue
-XshowSettings:vm show all vm related settings and continue
-XshowSettings:properties
                  show all property settings and continue
-XshowSettings:locale
                  show all locale related settings and continue

3 非Stable参数（-XX）
非Stable参数（-XX），此类参数各个jvm实现会有所不同，将来可能会随时取消，需要慎重使用（但是，这些参数往往是非常有用的）. 通过命令java -XX:+PrintFlagsFinal

[Global flags]
uintx AdaptiveSizeDecrementScaleFactor uintx AdaptiveSizeMajorGCDecayTimeScale uintx AdaptiveSizePausePolicy uintx AdaptiveSizePolicyColle uintx AdaptiveSizePolicyInitializingSteps uintx AdaptiveSizePolicyOutputInterval uintx AdaptiveSizePolicyWeight uintx AdaptiveSizeThroughPutPolicy uintx AdaptiveTimeWeight bool AdjustConcurrency bool AggressiveOpts intx AliasLevel bool AlignVector intx AllocateInstancePrefetchLines intx AllocatePrefetchDistance intx AllocatePrefetchInstr intx AllocatePrefetchLines intx AllocatePrefetchStepSize intx AllocatePrefetchStyle bool AllowJNIEnvProxy bool AllowNonVirtualCalls bool AllowParallelDefineClass bool AllowUserSignalHandlers bool AlwaysActAsServerClassMachine bool AlwaysCompileLoopMethods bool AlwaysLockClassLoader bool AlwaysPreTouch bool AlwaysRestoreFPU bool AlwaysTenure bool AssertOnSuspendWaitFailure bool AssumeMP intx AutoBoxCacheMax uintx AutoGCSelectPauseMillis intx BCEATraceLevel intx BackEdgeThreshold = 4 {product}
= 10 {product}
= 0 {product}
ctionCostMargin = 50 {product}
= 20 {product}
= 0 {product}
= 10 {product}
= 0 {product}
= 25 {product}
= false {product}
= false {product}
= 3 {C2 product}
= false {C2 product}
= 1 {product}
= 192 {product}
= 0 {product}
= 4 {product}
= 64 {product}
= 1 {product}
= false {product}
= false {product}
= false {product}
= false {product}
= false {product}
= false {product}
= false {product}
= false {product}
= false {product}
= false {product}
= false {product}
= true {product}
= 128 {C2 product}
= 5000 {product}
= 0 {product}
= 100000 {pd product}