xinhua wrote : i can not deploy undeploy app / shutdown start jboss for test You don't have to shutdown your existing JBossAS to do a test - you could run a second instance. xinhua wrote : i wonder if i can tune JBossAS to reduce memory usage Memory usage of any Java app (which includes JBossAS) is dictated by the heap space allocated. Thus you could, for example, reduce the 1GB heap you are currently allocating to 800MB to save space. But that 200MB of savings would be a negligible part of the 5.5GB you reported. See my presentation on tuning the heap: http://www.cecmg.de/doc/tagung_2007/agenda07/24-mai/2b3-peter-johnson/ind... You could also change the number of threads that handle HTTP request by editing the maxThreads attribute of the Connector tag in server.xml (in server/xxx/deploy/jboss-web.deployer). But reducing that can reduce the response time for your users (if they have to wait for an available thread), or even result in "server is busy" errors. Besides, if each thread uses only 8K, then 100 threads use less than 1MB, which is an insignificant part of the 5.5GB. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4166247#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...