With default configuration, if you use the "Shutdown and restart" or "Halt and restart" items from the context menu in the java applet in the web-console, or alternatively use twiddle or any jmx tool to invoke the exit or halt method from jboss.system:type=Server with an exitcode of 10 (so that run.(sh|bat) loops and restarts the server) , it doesn't restart the server because it exits with exit code 0 instead of whatever argument you give to the method.

This is due to the fact that jboss.shutdown.forceHalt is set to true by default, and that having forceHalt true makes the shutdown hook call Runtime.getRuntime().halt(0);

See http://anoncvs.forge.jboss.com/viewrep/JBoss/jboss-system/src/main/org/jboss/system/server/ServerImpl.java?r=1.62#l953