Tutorial by Examples

-XXaggressive is a collection of configurations that make the JVM perform at a high speed and reach a stable state as soon as possible. To achieve this goal, the JVM uses more internal resources at startup; however, it requires less adaptive optimization once the goal is reached. We recommend that y...

This option allows you to clear a TLA for references and values at TLA allocation time and pre-fetch the next chunk. When an integer, a reference, or anything else is declared, it has a default value of 0 or null (depending upon type). At the appropriate time, you will need to clear these references...

When used with -XXallocClearChunkSize, this option sets the size of the chunks to be cleared. If this flag is used but no value is specified, the default is 512 bytes. Usage: -XXallocClearChunks -XXallocClearChunkSize=<size>[k|K][m|M][g|G]

This option enables the use of call profiling for code optimizations. Profiling records useful runtime statistics specific to the application and can—in many cases—increase performance because JVM can then act on those statistics. Note: This option is supported with the JRockit JVM R27.3.0 and la...

This option disables the fat lock spin code in Java, allowing threads that block trying to acquire a fat lock go to sleep directly. Objects in Java become a lock as soon as any thread enters a synchronized block on that object. All locks are held (that is, stayed locked) until released by the locki...

This option disables the garbage collector strategy changes. Compaction heuristics and nursery size heuristics are not affected by this option. By default, the garbage collection heuristics are enabled. Usage: -XXdisableFatSpin

This option causes a dump file to be generated and allows you to specify the relative size of that file (that is, small, medium, or large). Usage: -XXdumpsize:<size> <size>DescriptionnoneDoes not generate a dump file.smallOn Windows, a small dump file is generated (on Linux a full c...

This option makes JRockit JVM exit on the first occurrence of an out of memory error. It can be used if you prefer restarting an instance of JRockit JVM rather than handling out of memory errors. Enter this command at startup to force JRockit JVM to exit on the first occurrence of an out of memory e...