anonymous wrote : my understanding is that Jboss start with the minimum memory configured to 128MB and keeps getting more as needed, but when the allocated memory is not used anymore (becomes Free memory), Jboss should return this memory to the OS No, that is not correct. The JVM, once it asks the OS for memory, will never release that memory back to the OS. If you do not want the JVM to consume 1.5GB of memory, do not set -Xmx that high. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4144545#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...