Hi Brian, Thanks for your info. There's same jboss-cache.jar both under web-inf/lib and server/all/lib, so I removed the one under web-inf/lib. Then I got another exception, java.lang.IllegalArgumentException: interface org.jboss.mx.util.MBeanProxyInstance is not visible from class loader | at java.lang.reflect.Proxy.getProxyClass(Proxy.java:353) | at java.lang.reflect.Proxy.newProxyInstance(Proxy.java:581) | at org.jboss.mx.util.MBeanProxyExt.create(MBeanProxyExt.java:345) | at org.jboss.mx.util.MBeanProxyExt.create(MBeanProxyExt.java:308) | at org.jboss.mx.util.MBeanProxyExt.create(MBeanProxyExt.java:283) | at com.letu.netprint.util.cache.BaseCacheManager.initCache(BaseCacheManager.java:101) | at com.letu.netprint.util.cache.BaseCacheManager.getCache(BaseCacheManager.java:120) | ... The stack trace is related with this code: MBeanServer server=MBeanServerLocator.locateJBoss(); | cache_=(PojoCacheMBean)MBeanProxyExt.create(PojoCacheMBean.class, "jboss.cache:service=testPojoCache", server); Seems it has problem to create the cache object now. Am I moving backward? Thanks, Steven View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3976068#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...