12 Replies Latest reply on Nov 18, 2004 12:25 PM by vitaly1

    ClassLoader can not find a MBean class that sits in the same

    vitaly1 Newbie

      Hi !

      I have a SAR file with one service that loads up other MBeans
      from my own Xml config file.
      The trouble is that the classloader can not find a class that sits
      in the same sar where the JBoss service class is?

      ie:
      server.createMBean("com.percussion.jmx.test.SimpleListener",
      getObjectName(),
      getMethodArguments(this, server),
      getJMXMethodSignature(this));

      ... 120 more

      Caused by: java.lang.ClassNotFoundException: com.percussion.jmx.test.SimpleListener
      at java.net.URLClassLoader$1.run(URLClassLoader.java:199)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.net.URLClassLoader.findClass(URLClassLoader.java:187)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:289)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:235)
      at org.jboss.mx.server.MBeanServerImpl.instantiate(MBeanServerImpl.java:1183)

        • 1. Re: ClassLoader can not find a MBean class that sits in the
          Dimitris Andreadis Master

          You need to use the classloader that loaded the 1st MBean, e.g:

          Object mybean = Class.forName("com.percussion.jmx.test.SimpleListener", true, this.getClass().getClassLoader()).newInstance();
          
          server.registerMBean(mybean, "mydomain:name=myname");
          


          There is also the createMBean() that takes the ObjectName of a classloader, but I'm not sure how to map the context thread classloader to the ObjectName under which it is registered.

          • 2. Re: ClassLoader can not find a MBean class that sits in the
            vitaly1 Newbie

            Wonder if this will work too?
            trying it now..

            ClassLoader cl = this.getClass().getClassLoader();
            obj = server.createMBean(className,
            getObjectName(),
            cl,
            getMethodArguments(this, server),
            getJMXMethodSignature(this));

            • 3. Re: ClassLoader can not find a MBean class that sits in the
              vitaly1 Newbie

              oops, it actually expects ObjectName loaderName
              how do I get ObjectName of the loader?

              • 4. Re: ClassLoader can not find a MBean class that sits in the
                vitaly1 Newbie

                If I can not use this method, that means I need
                to do all the introspection, call a constructor myself
                isn't there a better way to do it?

                ObjectInstance createMBean(java.lang.String className, ObjectName name, ObjectName loaderName, java.lang.Object[] params, java.lang.String[] signature)

                • 5. Re: ClassLoader can not find a MBean class that sits in the
                  vitaly1 Newbie

                  So, I ended up with this code:
                  The trouble is it not working just like before - ClassNotFoundException :(
                  eflectionException: Class not found: com.percussion.jmx.test.SimpleListener Cause: java.lang.ClassNotFoundException: com.percussion.jmx.test.SimpleListener

                  ClassLoader cl = this.getClass().getClassLoader();

                  Class clazz = Class.forName(className,
                  true,
                  this.getClass().getClassLoader());

                  Constructor handlerCtor = clazz.getConstructor(
                  getMethodSignature(this));

                  java.lang.Object beanInst =
                  handlerCtor.newInstance( getMethodArguments(this, server) );

                  obj = server.registerMBean(beanInst, getObjectName());

                  • 6. Re: ClassLoader can not find a MBean class that sits in the
                    Dimitris Andreadis Master

                    out of curiocity, what are those:

                    getMethodSignature(this)
                    getMethodArguments(this, server)
                    getObjectName()

                    Isn't you 1st mbean loaded using a -service.xml or .sar archive?

                    What is the use case you are trying to implement?

                    • 7. Re: ClassLoader can not find a MBean class that sits in the
                      vitaly1 Newbie

                      Hi !
                      those are my methods :) (derived from MX4J) one gets signature Class[]
                      another actual values and getObject gives ObjectName instance
                      The use case is like this:
                      1. I want to be able to load the same JMX beans on JBoss, Bea, etc.
                      2. To do the above I defined my own xml config file (enhaced MX4J one)
                      3. For each app server I will build one app server specific loader; in JBoss
                      case that is a service MBean
                      4. So I have a sar with one JBoss specific MBean that creates another MBean (non JBoss specific) that guy loads up my xml config file and creates all the rest of the beans, creates listeners, relationships, etc.

                      All these classes sit inside the same SAR file, which really puzzles me why JBoss can not find simple Bean classes that are practically sit next to the service class only in a different package?

                      • 8. Re: ClassLoader can not find a MBean class that sits in the
                        Dimitris Andreadis Master

                        The example code I showed you, works for at least one component I know. From which line exactly the exception comes from? (fromName(), newInstance()?)

                        Try calling the default CTOR.

                        Also from the 3 methods getXXX() it seems as if you try to replicate the same running MBean, e.g. getObjectName() what does it return?

                        Show the mbean descriptor, too.

                        • 9. Re: ClassLoader can not find a MBean class that sits in the
                          vitaly1 Newbie

                          Dimitris,

                          I sent you my sources, see if something jumps out

                          • 10. Re: ClassLoader can not find a MBean class that sits in the
                            vitaly1 Newbie

                            1. JBoss loads us PSJmxJBossService
                            that one creates another MBean
                            PSJmxConfigurationLoader
                            2. PSJmxConfigurationLoader fetches my xml
                            file with all the beans definitions in it and
                            uses PSJmxDefaultConfigurationBuilder
                            to load all those beans up
                            3. The PSJmxDefaultConfigurationBuilder
                            has one inner class for each xml node in
                            the xml config file under com.percussion.jmx.config

                            ie: node is first parsed then there
                            is a second run when PSJmxDefaultConfigurationBuilder
                            instantiates all those MBeans and registers
                            them with MBeanServer

                            • 11. Re: ClassLoader can not find a MBean class that sits in the
                              Dimitris Andreadis Master

                              Could you be a little more careful (or just buy some JBoss support)? Your configuration file tries to load mx4j classes. If you comment that out, it works.

                              Caused by: java.lang.ClassNotFoundException: No ClassLoaders found for: mx4j.too
                              ls.adaptor.http.HttpAdaptor
                               at org.jboss.mx.loading.LoadMgr3.beginLoadTask(Unknown Source)
                               at org.jboss.mx.loading.RepositoryClassLoader.loadClassImpl(Unknown Sour
                              ce)
                               at org.jboss.mx.loading.RepositoryClassLoader.loadClass(Unknown Source)
                               at java.lang.ClassLoader.loadClass(ClassLoader.java:235)
                               at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:302)
                               at java.lang.Class.forName0(Native Method)
                               at java.lang.Class.forName(Class.java:219)
                               at com.percussion.jmx.config.PSJmxDefaultConfigurationBuilder$Create.con
                              figure(PSJmxDefaultConfigurationBuilder.java:333)
                               ... 72 more
                              


                               <!--
                               <create className="mx4j.tools.adaptor.http.HttpAdaptor" objectName="connectors:type=http" loaderName="null">
                               <arg type="int" name="port">9090</arg>
                               <arg type="string" name="host">localhost</arg>
                               </create>
                              
                               <create className="mx4j.tools.adaptor.http.XSLTProcessor" objectName="connectors:type=http,processor=xslt" loaderName="null"/>
                              
                               <call objectName="connectors:type=http" attribute="ProcessorNameString">
                               <arg type="string" name="connName">connectors:type=http,processor=xslt</arg>
                               </call>
                               <call objectName="connectors:type=http" operation="start"/>
                              -->
                              



                              • 12. Re: ClassLoader can not find a MBean class that sits in the
                                vitaly1 Newbie

                                Thanks a lot!

                                The above MX4J stuff got in by accident, but the bigger issue was that I left a older sar under /lib
                                so, I kept trying and trying not realizing that JBoss
                                was actually running my older code!

                                I appreciate your help

                                Thanks,
                                -Vitaly