The Java Virtual Machine has a jps tool wich is a bit like the ps command.
jps lists all java Processes of a user.
You can find the man page at http://java.sun.com/j2se/1.5.0/docs/tooldocs/share/jps.html.
I'm using it with the parameters -l (long listing) and -m (arguments) most of the time:
/usr/java/bin/jps -lm
Here are some more examples:
List all java processes: jps
55719 hourglass.jar 51299 jEdit 51610 Main 56026 Jps
Long listing: jps -l
55719 /Users/andreas/.my/pkg/hourglass-0.6.1/lib/hourglass.jar 51299 /Applications/jEdit 56042 sun.tools.jps.Jps 51610 org.netbeans.Main
List arguments: jps -m
55719 hourglass.jar 56051 Jps -m 51299 jEdit 4.2/jedit.jar 51610 Main --userdir /Users/andreas/Library/Application Support/visualvm/1.0.1 --branding visualvm
Java VM parameters: jps -v
56053 Jps -Dapplication.home=/System/Library/Frameworks/JavaVM.framework/Versions/1.6.0/Home -Xms8m 55719 hourglass.jar 51299 jEdit 51610 Main -Djdk.home=/System/Library/Frameworks/JavaVM.framework/Versions/1.6/Home -Dnetbeans.system_http_proxy=DIRECT -Dnetbeans.system_http_non_proxy_hosts= -Dnetbeans.dirs=bin/..//visualvm:bin/..//profiler2: -Dnetbeans.home=/Users/andreas/Downloads/visualvm/platform7 -Dcom.apple.mrj.application.apple.menu.about.name=visualvm -Xms24m -Xmx192m -Dnetbeans.accept_license_class=com.sun.tools.visualvm.modules.startup.AcceptLicense -Dsun.jvmstat.perdata.syncWaitMs=10000