Hi, peter, thank you for your advice. yes you right, i should contact Sun or Oracle, why i did put the question here is because maybe someone here encoountered the same problem as mine and know how to solve it. And also, i am not sure it would be jvm problem so i wonder if i can tune JbossAS to reduce memory usage. Sofar, my webservice and Oracle Timesten db which takes more then 10G memory runs on the same productive server(16G+Solaris64bit) and i can not deploy undeploy app / shutdown start jboss for test. (unfortunately i do not have a sever with same equipment for test.) if i run my webservice (remote connect Timesten with client driver) on a 32bitSolaris with 4G memory, i didnot see any unormal memory usage. Today, i wonder if solaris really take my -Xss def and will install dtrace script on server to see how many memory each thread used. Yes, surely will ask Sun about this also . View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4166235#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...