Java Options
If you launch from a shell the command: java -? 
this will return the list of available options for the command. 
By running the command: java -X
instead will be shown a list of non-standard options.
Note: This list may vary from version to version of Java and is subject to change (between versions) without warning or notice. 
Options that are specified with -XX are not stable and are not recommended for casual use. 
These options are subject to change without notice. 
| -Xmx900m  | 
maximum Java heap size (900 megabytes) | 
| -XX:MaxPermSize=384m | 
maximum Size of the Permanent Generation (384 megabytes) | 
| -Xms512m | 
initial Java heap size | 
| -XX:MaxNewSize=24m | 
Maximum size of new generation | 
| -XX:NewSize=24m | 
Default size of new generation  | 
| -XX:+UseParNewGC | 
Parallel Young Generation garbage collector (for multiprocessor machines) | 
| -XX:+CMSParallelRemarkEnabled | 
Attempt to descrease remark pauses when used with -XX:+UseParNewGC | 
| -XX:+UseConcMarkSweepGC | 
Enable the concurrent low pause collector  | 
| -Dorg.apache.el.parser.COERCE_TO_ZERO=false  | 
If true, when coercing expressions to numbers "" and null will be coerced to zero as required by the specification. If not specified, the default value of true will be used. | 
 
Note: Many of the options presented are related to JVM 1.4 in particular, refer to the following URLs:
http://java.sun.com/docs/hotspot/gc1.4.2/faq.html
http://www.petefreitag.com/articles/gctuning/ 
Should therefore be careful when using these options on a JVM 1.6.
For the latest list of available options for the J2SE 6.0 refer to the following documentation:
 
JVM 1.6 - J2SE 6
Java HotSpot VM Options
http://java.sun.com/javase/technologies/hotspot/vmoptions.jsp
Java SE 6 HotSpot[tm] Virtual Machine Garbage Collection Tuning
http://java.sun.com/javase/technologies/hotspot/gc/gc_tuning_6.html
http://java.sun.com/performance/reference/whitepapers/6_performance.html 
http://collab.sakaiproject.org/pipermail/sakai-dev/2009-September/003682.html