Classloader

My first try at using CGLib from a Netbeans RCP ended up in a ClassNotFoundException for net.sf.cglib.proxy.Factory I had two modules, MainModule and cglib and MainModule was depending on cglib. And the following snippet was raising the ClassNotFoundException. Enhancer enhancer = new Enhancer(); enhancer.setSuperclass(Graph.class); enhancer.setCallback(NoOp.INSTANCE); Graph g = (Graph) enhancer.create(new Class[]{FrameListener.class,InterpreterAbstraction.class},new Object[]{fl,ia}) ; As I later found out from Enhancer documentation and DevFaqClassLoaders it seems that Enhancer it taking the System class loader instead of taking the Module classloader. I explicitly set the classloader used by the Enhancer via the setClassLoader method and now it seems to work. ...

Or java.lang.NoClassDefFoundError: javax/servlet/ServletContextListener for that matter. NoClassDefFoundError on HttpSessionListener , ServletListener , ServletContextListener, etc. can be caused by a custom classloader like Sysdeo DevLoader (I use it with Eclipse) in you Context definition in the Tomcat’s server.xml file. <Loader classname="org.apache.catalina.loader.DevLoader" reloadable="true" debug="1" /> the solution: add useSystemClassLoaderAsParent="false" to the Loader <Loader classname="org.apache.catalina.loader.DevLoader" reloadable="true" debug="1" useSystemClassLoaderAsParent="false"/> This should do the trick. More information here and here