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Behavioral Options（行為引數）
Option and Default Value Description
| -XX:-AllowUserSignalHandlers |
Do not complain if the application installs signal handlers. (Relevant to Solaris and Linux only.) 允許應用程式安裝訊號處理器（僅在solaris和linux起作用。） |
| -XX:AltStackSize=16384 |
Alternate signal stack size (in Kbytes). (Relevant to Solaris only, removed from 5.0.) 備用訊號棧大小（僅在solaris起作用，從5.0起已經刪除） |
| -XX:-DisableExplicitGC |
Disable calls to System.gc(), JVM still performs garbage collection when necessary. 禁止呼叫System.gc(), JVM 依然在必要時執行垃圾回收。 |
| -XX:+FailOverToOldVerifier |
Fail over to old verifier when the new type checker fails. (Introduced in 6.) 當新的型別檢查器失敗時轉移到舊的型別檢查器上（從6.0開始引進） |
| -XX:+HandlePromotionFailure |
The youngest generation collection does not require a guarantee of full promotion of all live objects. (Introduced in 1.4.2 update 11) [5.0 and earlier: false.] 最年輕一代的垃圾收集不需要保證所有的活動物件完全升級。 |
| -XX:+MaxFDLimit |
Bump the number of file descriptors to max. (Relevant to Solaris only.) 檔案描述符設定到最大。（只與solaris相關） |
| -XX:PreBlockSpin=10 |
Spin count variable for use with -XX:+UseSpinning. Controls the maximum spin iterations allowed before entering operating system thread synchronization code. (Introduced in 1.4.2.) 在啟用-XX:+UseSpinning 的情況下，設定旋轉計數變數，來控制進入系統的執行緒同步程式碼之前，允許的最大旋轉迭代次數。（在1.4.2引入） |
| -XX:-RelaxAccessControlCheck |
Relax the access control checks in the verifier. (Introduced in 6.) 在驗證器裡放鬆訪問控制的檢查。（在6.0引入） |
| -XX:+ScavengeBeforeFullGC |
Do young generation GC prior to a full GC. (Introduced in 1.4.1.) 最年輕一代GC優先於全域性GC（在1.4.1引入） |
| -XX:+UseAltSigs |
Use alternate signals instead of SIGUSR1 and SIGUSR2 for VM internal signals. (Introduced in 1.3.1 update 9, 1.4.1. Relevant to Solaris only.) 用備份訊號代替JVM的SIGUSR1 和 SIGUSR2 （只和solaris相關） |
| -XX:+UseBoundThreads |
Bind user level threads to kernel threads. (Relevant to Solaris only.) 繫結使用者級別的執行緒到核心執行緒。（只與solaris有關） |
| -XX:-UseConcMarkSweepGC |
Use concurrent mark-sweep collection for the old generation. (Introduced in 1.4.1) 對老一代物件區使用同步標記並摖除垃圾收集演算法（從1.4.1引進） |
| -XX:+UseGCOverheadLimit |
Use a policy that limits the proportion of the VM's time that is spent in GC before an OutOfMemory error is thrown. (Introduced in 6.) 在OutOfMemory錯誤丟擲之前，採用限制花費在GC上的時間在VM比例幅度的策略。（在6.0引入） |
| -XX:+UseLWPSynchronization |
Use LWP-based instead of thread based synchronization. (Introduced in 1.4.0. Relevant to Solaris only.) 用基於LWP的同步來替代基於執行緒的同步。（從1.4.0引入，只和solaris相關） |
| -XX:-UseParallelGC |
Use parallel garbage collection for scavenges. (Introduced in 1.4.1) 用並行垃圾收集的演算法來清除物件。（從1.4.1起引入） |
| -XX:-UseParallelOldGC |
Use parallel garbage collection for the full collections. Enabling this option automatically sets -XX:+UseParallelGC. (Introduced in 5.0 update 6.) 對整個收集使用並行垃圾收集演算法，並自動設定-XX:+UseParallelGC。（從5.0引入升級到6.0） |
| -XX:-UseSerialGC |
Use serial garbage collection. (Introduced in 5.0.) 使用系列垃圾收集演算法（從5.0起引入） |
| -XX:-UseSpinning |
Enable naive spinning on Java monitor before entering operating system thread synchronizaton code. (Relevant to 1.4.2 and 5.0 only.) [1.4.2, multi-processor Windows platforms: true] 在進入系統執行緒同步程式碼之前在JAVA監視器上使用原生的旋轉。 （只與1.4.2和5.0相關，1.4.2只有在多處理器的windows平臺才有效） |
| -XX:+UseTLAB |
Use thread-local object allocation (Introduced in 1.4.0, known as UseTLE prior to that.) [1.4.2 and earlier, x86 or with -client: false] 用本地執行緒物件分配記憶體（從1.4.0引入，UseTLE優先於該選項，- client: 無效） |
| -XX:+UseSplitVerifier |
Use the new type checker with StackMapTable attributes. (Introduced in 5.0.)[5.0: false] 用新型別檢查器裡用StackMapTable屬性。（從5.0開始引入） |
| -XX:+UseThreadPriorities |
Use native thread priorities. 優先用本地執行緒 |
| -XX:+UseVMInterruptibleIO |
Thread interrupt before or with EINTR for I/O operations results in OS_INTRPT. (Introduced in 6. Relevant to Solaris only.) 在用I/O操作導致的OS_INTRPT或者使用執行緒終斷。 （在6.0引入，只與solaris有關） |
Performance Options（效能引數）
Option and Default Value Description
| -XX:+AggressiveOpts |
Turn on point performance compiler optimizations that are expected to be default in upcoming releases. (Introduced in 5.0 update 6.) 開啟效能編譯器優化（在5.0引入升級到6.0） |
| -XX:CompileThreshold=10000 |
Number of method invocations/branches before compiling [-client: 1,500] 編譯前方法呼叫/分支的數目【-client預設是1500】 |
| -XX:LargePageSizeInBytes=4m |
Sets the large page size used for the Java heap. (Introduced in 1.4.0 update 1.) [amd64: 2m.] 設定用於Java堆的最大頁的尺寸 |
| -XX:MaxHeapFreeRatio=70 |
Maximum percentage of heap free after GC to avoid shrinking. 為了避免重疊，GC後最大空閒的堆的最大百分比。 |
| -XX:MaxNewSize=size |
Maximum size of new generation (in bytes). Since 1.4, MaxNewSize is computed as a function of NewRatio. [1.3.1 Sparc: 32m; 1.3.1 x86: 2.5m.] 新生代的最大尺寸。從1.4開始，MaxNewSize由NewRatio的函式計算而來。 |
| -XX:MaxPermSize=64m |
Size of the Permanent Generation. [5.0 and newer: 64 bit VMs are scaled 30% larger; 1.4 amd64: 96m; 1.3.1 -client: 32m.] 永久生代的尺寸。 |
| -XX:MinHeapFreeRatio=40 |
Minimum percentage of heap free after GC to avoid expansion. 為了避免擴張，GC後最小空閒堆的百分比。 |
| -XX:NewRatio=2 |
Ratio of new/old generation sizes. [Sparc -client: 8; x86 -server: 8; x86 -client: 12.]-client: 4 (1.3) 8 (1.3.1+), x86: 12] 新生代/老生代的比分比。 |
| -XX:NewSize=2.125m |
Default size of new generation (in bytes) [5.0 and newer: 64 bit VMs are scaled 30% larger; x86: 1m; x86, 5.0 and older: 640k] 預設的新生代大小。 |
| -XX:ReservedCodeCacheSize=32m |
Reserved code cache size (in bytes) - maximum code cache size. [Solaris 64-bit, amd64, and -server x86: 48m; in 1.5.0_06 and earlier, Solaris 64-bit and and64: 1024m.] 保留的程式碼快取大小-最大的程式碼快取大小 |
| -XX:SurvivorRatio=8 |
Ratio of eden/survivor space size [Solaris amd64: 6; Sparc in 1.3.1: 25; other Solaris platforms in 5.0 and earlier: 32] 銷燬/保留的空間比例 |
| -XX:TargetSurvivorRatio=50 |
Desired percentage of survivor space used after scavenge. 清除後期望的保留空間比率 |
| -XX:ThreadStackSize=512 |
Thread Stack Size (in Kbytes). (0 means use default stack size) [Sparc: 512; Solaris x86: 320 (was 256 prior in 5.0 and earlier); Sparc 64 bit: 1024; Linux amd64: 1024 (was 0 in 5.0 and earlier); all others 0.] 執行緒棧大小 |
| -XX:+UseBiasedLocking |
Enable biased locking. For more details, see this tuning example. (Introduced in 5.0 update 6.) [5.0: false] 使用偏鎖 |
| -XX:+UseFastAccessorMethods |
Use optimized versions of Get<Primitive>Field. 使用優化版本的Get<Primitive>方法。 |
| -XX:-UseISM |
Use Intimate Shared Memory. [Not accepted for non-Solaris platforms.] For details, see Intimate Shared Memory. 使用親密共享空間【對非solaris平臺無效】 |
| -XX:+UseLargePages |
Use large page memory. (Introduced in 5.0 update 5.) For details, see Java Support for Large Memory Pages. 使用large page memory |
| -XX:+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] 使用Multiple Page Size Support |
| -XX:+UseStringCache | Enables caching of commonly allocated strings. 使用常用字串快取 |
| -XX:AllocatePrefetchLines=1 |
Number of cache lines to load after the last object allocation using prefetch instructions generated in JIT compiled code. Default values are 1 if the last allocated object was an instance and 3 if it was an array. 用預取指令分配一個物件，快取程式碼的行數。預設是1，陣列是3. |
| -XX:AllocatePrefetchStyle=1 |
Generated code style for prefetch instructions. 預取指令的產生程式碼風格： 0-沒有預取指令， 1-每一次分配記憶體就執行預取指令， 2-當執行預取程式碼指令時，用TLAB分配水印指標指向門。 |
| -XX:+UseCompressedStrings |
Use a byte[] for Strings which can be represented as pure ASCII. (Introduced in Java 6 Update 21 Performance Release) 用byte[] 代替字串（從Java6開始引入） |
| -XX:+OptimizeStringConcat |
Optimize String concatenation operations where possible. (Introduced in Java 6 Update 20) 可能的話優化字串連線操作（從Java6引入） |
Debugging Options（dubug引數）
Option and Default Value Description
| -XX:-CITime |
Prints time spent in JIT Compiler. (Introduced in 1.4.0.) 列印JIT編譯器花費的時間（從1.4.0引入） |
| -XX:ErrorFile=./hs_err_pid<pid>.log |
If an error occurs, save the error data to this file. (Introduced in 6.) 錯誤發生時，把錯誤儲存到一個指定檔案。 |
| -XX:-ExtendedDTraceProbes |
Enable performance-impacting dtrace probes. (Introduced in 6. Relevant to Solaris only.) 啟用performance-impacting dtrace跟蹤（從6.0引入，只在solaris有效） |
| -XX:HeapDumpPath=./java_pid<pid>.hprof |
Path to directory or filename for heap dump. Manageable. (Introduced in 1.4.2 update 12, 5.0 update 7.) 堆dump檔案的存放目錄。（從1.4.2引入） |
| -XX:-HeapDumpOnOutOfMemoryError |
Dump heap to file when java.lang.OutOfMemoryError is thrown.Manageable. (Introduced in 1.4.2 update 12, 5.0 update 7.) 當丟擲異常java.lang.OutOfMemoryError 時，Dump heap 到檔案。（從1.4.2引入） |
| -XX:OnError="<cmd args>;<cmd args>" |
Run user-defined commands on fatal error. (Introduced in 1.4.2 update 9.) 在致命錯誤發生時執行使用者定義命令（從1.4.2引入） |
| -XX:OnOutOfMemoryError="<cmd args>; <cmd args>" |
Run user-defined commands when an OutOfMemoryError is first thrown. (Introduced in 1.4.2 update 12, 6) 執行使用者定義命令當一個OutOfMemoryError 異常丟擲時。 （從1.4.2引入） |
| -XX:-PrintClassHistogram |
Print a histogram of class instances on Ctrl-Break. Manageable. (Introduced in 1.4.2.) The jmap -histo command provides equivalent functionality. Ctrl-Break列印類例項的直方圖（從1.4.2引入） |
| -XX:-PrintConcurrentLocks |
Print java.util.concurrent locks in Ctrl-Break thread dump.Manageable. (Introduced in 6.) The jstack -l command provides equivalent functionality. 列印java.util.concurrent 鎖 |
| -XX:-PrintCommandLineFlags |
Print flags that appeared on the command line. (Introduced in 5.0.) 列印在命令列中的標誌（從5.0引入） |
| -XX:-PrintCompilation |
Print message when a method is compiled. 當方法被編譯時列印訊息 |
| -XX:-PrintGC |
Print messages at garbage collection. Manageable. 垃圾收集時列印訊息 |
| -XX:-PrintGCDetails |
Print more details at garbage collection. Manageable. (Introduced in 1.4.0.) 垃圾收集時列印具體資訊 |
| -XX:-PrintGCTimeStamps |
Print timestamps at garbage collection. Manageable (Introduced in 1.4.0.) 垃圾收集時列印時間戳（從1.40引入） |
| -XX:-PrintTenuringDistribution |
Print tenuring age information. 列印任期年紀資訊 |
| -XX:-TraceClassLoading |
Trace loading of classes. 跟蹤正在載入的類 |
| -XX:-TraceClassLoadingPreorder |
Trace all classes loaded in order referenced (not loaded). (Introduced in 1.4.2.) 按順序跟蹤所有已經載入的類（從1.4.2引入） |
| -XX:-TraceClassResolution |
Trace constant pool resolutions. (Introduced in 1.4.2.) 跟蹤常量池解析度（從1.4.2引入） |
| -XX:-TraceClassUnloading |
Trace unloading of classes. 跟蹤正在上傳的類 |
| -XX:-TraceLoaderConstraints |
Trace recording of loader constraints. (Introduced in 6.) 跟蹤載入器的限制記錄（從6.0引入） |
| -XX:+PerfSaveDataToFile |
Saves jvmstat binary data on exit. 退出時儲存jvmstat二進值資料 |
| -XX:ParallelGCThreads= |
Sets the number of garbage collection threads in the young and old parallel garbage collectors. The default value varies with the platform on which the JVM is running. 設定在青年和老年並行垃圾收集程式的收集執行緒的數目，預設值根據JVM執行的平臺變化而變化。 |
| -XX:+UseCompressedOops |
Enables the use of compressed pointers (object references represented as 32 bit offsets instead of 64-bit pointers) for optimized 64-bit performance with Java heap sizes less than 32gb. 使用compressed pointers |
| -XX:+AlwaysPreTouch |
Pre-touch the Java heap during JVM initialization. Every page of the heap is thus demand-zeroed during initialization rather than incrementally during application execution. 當JVM初始化時預先對Java堆進行預先摸底 |
| -XX:AllocatePrefetchDistance= |
Sets the prefetch distance for object allocation. Memory about to be written with the value of new objects is prefetched into cache at this distance (in bytes) beyond the address of the last allocated object. Each Java thread has its own allocation point. The default value varies with the platform on which the JVM is running. 為物件分配設定預取距離。 |
| -XX:InlineSmallCode= |
Inline a previously compiled method only if its generated native code size is less than this. The default value varies with the platform on which the JVM is running. 當生成原生程式碼的大小小於給定的值時，內聯這個預編譯方法。 |
| -XX:MaxInlineSize=35 |
Maximum bytecode size of a method to be inlined. 內聯一個方法的最大位元組碼大小 |
| -XX:FreqInlineSize= |
Maximum bytecode size of a frequently executed method to be inlined. The default value varies with the platform on which the JVM is running. 經常執行方法內聯的最大位元組大小 |
| -XX:LoopUnrollLimit= |
Unroll loop bodies with server compiler intermediate representation node count less than this value. The limit used by the server compiler is a function of this value, not the actual value. The default value varies with the platform on which the JVM is running. 代表節點數目小於給定值時開啟迴圈體 |
| -XX:InitialTenuringThreshold=7 |
Sets the initial tenuring threshold for use in adaptive GC sizing in the parallel young collector. The tenuring threshold is the number of times an object survives a young collection before being promoted to the old, or tenured, generation. 為自適應GC設定保有年齡閥值。就是一個物件被升級到年老，中年的時代的次數。 |
| -XX:MaxTenuringThreshold= |
Sets the maximum tenuring threshold for use in adaptive GC sizing. The current largest value is 15. The default value is 15 for the parallel collector and is 4 for CMS. 設定最大年齡保有閥值。當前最大值是15. |