gistfile1.txt

-Xincgc
Enable the incremental garbage collector. The incremental garbage collector, which is off by default, will eliminate occasional garbage-collection pauses during program execution. However, it can lead to a roughly 10% decrease in overall GC performance.

-XX:+AggressiveOpts
Turn on point performance compiler optimizations that are expected to be default in upcoming releases. 

-XX:+UseFastAccessorMethods
Use optimized versions of Get<Primitive>Field.

-XX:-UseConcMarkSweepGC
Use concurrent mark-sweep collection for the old generation.

-XX:+UseParNewGC
When this collector kicks in, all application threads are stopped, and the copying collection proceeds using one thread (which means only one CPU even if on a multi-CPU machine). This is known as a stop-the-world collection, because basically the JVM pauses everything else until the collection is completed.
The parallel copying collector (-XX:+UseParNewGC). Like the original copying collector, this is a stop-the-world collector. However this collector parallelizes the copying collection over multiple threads, which is more efficient than the original single-thread copying collector for multi-CPU machines (though not for single-CPU machines). This algorithm potentially speeds up young generation collection by a factor equal to the number of CPUs available, when compared to the original singly-threaded copying collector.

-XX:+CMSIncrementalPacing
Enables automatic pacing. The incremental mode duty cycle is automatically adjusted based on statistics collected while the JVM is running.

-XX:ParallelGCThreads=n
Sets the number of threads used during parallel phases of the garbage collectors. The default value varies with the platform on which the JVM is running.