http://java.sun.com/docs/hotspot/VMOptions.html

-Xms:
	Sets the initial size of the heap. 


-Xmx:
	Sets the maximum size of the heap.

-Xmn: 	
	Set the size of the young generation (available beginning in J2SE 1.4.0). 

-XX:LargePageSizeInBytes:
	Sets the large page size used for the Java heap. Set to 2m when running 32-bit
	JVM 		on Solaris 10 x86 with AMD64 CPUs. Solaris Only. 
	Defaults (SPARC: 8m, x86: 4m, x86_64: 2m)

-Xbatch:
	Disables background compilation.

-Xss:	
	Sets the Java thread stack size.

-XX:+UseParallelGC: 
	Use parallel garbage collection for the eden (young) generation (available 		beginning in J2SE 1.4.0)

-XX:ParallelGCThreads=N:
	Sets the number of parallel GC threads for both the young and old parallel GC.


-XX:+UseParallelOldGC: 
	Use parallel garbage collection for the tenured (old) generation (available 		beginning in J2SE 5.0_06)

-XX:ParallelGCThreads=N:
	Sets the number of parallel GC threads for both the young and old parallel GC.

-XX:+AggressiveOpts: 
	Turns on point performance optimizations that are expected to be default in upcoming 	releases.   The changes grouped by this flag are minor changes to JVM runtime 			compiled code and not distinct performance features (such as Biased Locking and 		Parallel Old GC).  This is a good flag to test the JVM engineering team's latest 		performance tweaks that you'll see in upcoming releases. (Available beginning in 		J2SE 5.0_06)