I recently upgraded my Jboss from 4.2.1 to 5.0.1. In Jboss 4 I used the following options for enabling remote JMX JAVA_OPTS="${JAVA_OPTS} -Dcom.sun.management.jmxremote.port=12345" JAVA_OPTS="${JAVA_OPTS} -Dcom.sun.management.jmxremote.authenticate=false" JAVA_OPTS="${JAVA_OPTS} -Dcom.sun.management.jmxremote.ssl=false" JAVA_OPTS="${JAVA_OPTS} -Djboss.platform.mbeanserver" JAVA_OPTS="${JAVA_OPTS} Djavax.management.builder.initial=org.jboss.system.server.jmx.MBeanServerBuilderImpl" Starting Jboss 5 with the same options produces this error: javax.management.JMRuntimeException: Failed to load MBeanServerBuilder class org.jboss.system.server.jmx.MBeanServerBuilderImpl: java.lang.ClassNotFoundException: org.jboss.system.server.jmx.MBeanServerBuilderImpl at javax.management.MBeanServerFactory.checkMBeanServerBuilder(MBeanServerFactory.java:480) at javax.management.MBeanServerFactory.getNewMBeanServerBuilder(MBeanServerFactory.java:511) at javax.management.MBeanServerFactory.newMBeanServer(MBeanServerFactory.java:298) at javax.management.MBeanServerFactory.createMBeanServer(MBeanServerFactory.java:213) at javax.management.MBeanServerFactory.createMBeanServer(MBeanServerFactory.java:174) at sun.management.ManagementFactory.createPlatformMBeanServer(ManagementFactory.java:302) at java.lang.management.ManagementFactory.getPlatformMBeanServer(ManagementFactory.java:504) at sun.management.jmxremote.ConnectorBootstrap.initialize(ConnectorBootstrap.java:392) at sun.management.Agent.startAgent(Agent.java:127) at sun.management.Agent.startAgent(Agent.java:239) Caused by: java.lang.ClassNotFoundException: org.jboss.system.server.jmx.MBeanServerBuilderImpl at java.net.URLClassLoader$1.run(URLClassLoader.java:200) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:188) at java.lang.ClassLoader.loadClass(ClassLoader.java:307) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:252) at javax.management.MBeanServerFactory.loadBuilderClass(MBeanServerFactory.java:423) at javax.management.MBeanServerFactory.checkMBeanServerBuilder(MBeanServerFactory.java:465) ... 9 more Exception thrown by the agent : javax.management.JMRuntimeException: Failed to load MBeanServerBuilder class org.jboss.system.server.jmx.MBeanServerBuilderImpl: java.lang.ClassNotFoundException: org.jboss.system.server.jmx.MBeanServerBuilderImpl I found a few threads about similar topics (http://www.jboss.org/?module=bb&op=viewtopic&p=4026239 , http://www.jboss.org/community/docs/DOC-10521), but these don't help. Any ideas? Thank in advance, Vitaly