What operating system? Based on the command line, the heap will never use more than 1/2GB, so the memory usage must be coming from some other place. One possibility is from the threads running - each thread uses memory (typically 1MB, but that all depends on the machine architecture and the OS). What have you done to monitor memory usage of the JVMs process? View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4224416#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...