questions on the defaultCachTimeout

[jdsignature]

Does anybody know when to apply the DefaultCachTimeout = 0 to flush the user credentials, and when to use the following code to flush? thanks,


ObjectName jaasMgr = new ObjectName("jboss.security:service=JaasSecurityManager");
Object[] params = {domain};
String[] signature = {"java.lang.String"};
MBeanServer server = (MBeanServer) MBeanServerFactory.findMBeanServer(null).get(0);
server.invoke(jaasMgr, "flushAuthenticationCache", params, signature);