Kabir Khan, Compile time aopc is working fine with websphere. But I have to use load time weaving as per the requirement Kabir Khan\flavia rainone, I also believe there is something wrong with class loader. There are two ways to apply classpath, javaagent and jboss aop path in websphere First way There is a server start up file (startserver.bat) under bin directory. I have made following modifications in JVM settings 1. I have added jboss aop dependency jar files to classpath 2. I have added following javaagent variable. -javaagent:D:\jboss-aop_1.5.5.GA\lib-50\jboss-aop-jdk50.jar 3. I have added following -X option -Xbootclasspath/p:%JAVA_HOME%\lib\tools.jar;%JAVA_HOME%\jre\lib\core.jar Now i am able to start the server without any error and exception. Application also running but aspect instrumentation is not happening Second way: There is configuration file (server.xml) for websphere server. In that XML file there is a tag called ?jvmEntries?. I have made following modifications in the ?jvmEntries? tag 1. I have added jboss aop dependency jar files to classpath 2. I have added following jar files in bootclasspath and also in classpath %JAVA_HOME%\lib\tools.jar;%JAVA_HOME%\jre\lib\core.jar 3. I have added -javaagent:D:\jboss-aop_1.5.5.GA\lib-50\jboss-aop-jdk50.jar option under "genericJvmArguments" attribute. The server is not starting properly it is giving same exception as mentioned earlier. If I remove javaagent option the server is starting successfully. But javaagent option is mandatory for Jboss aop application. There is no strong documentation for all the JVM options in websphere documentation. So I have done above changes trial and error method. Please help me View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4034972#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...