1 Reply Latest reply: Jun 7, 2011 12:03 AM by Mohammad Norouzi RSS

Adding interface to an existing class

Mohammad Norouzi Novice



I have a class which is in legacy system and we cannot change the class. I need to create a java proxy for that class but this is a class without interface. So I have created an interface and write the following code to add this interface to that class at runtime but the class.getInterfaces() method still returns no interface!



public class Main {




    public static void main(String[] args) throws Exception {



        AnAbstractClass instance = new AClassFromAbstract();//instance.getClass().getInterfaces()

        Object proxy = Proxy.newProxyInstance(ProxyIntAnAbstractClass.class.getClassLoader(),

                new Class[] {ProxyIntAnAbstractClass.class},

                new MyInvocationHandler(instance));


        ProxyIntAnAbstractClass instance2 = (ProxyIntAnAbstractClass) proxy;





    public static Class createInterface() throws Exception{

        ClassPool pool = ClassPool.getDefault();

        ClassPath cp = new ClassClassPath(AnAbstractClass.class);




        CtClass myinterface = pool.get("com.mmm.test.proxy.ProxyIntAnAbstractClass");



        CtClass tclass = pool.getCtClass("com.mmm.test.proxy.AnAbstractClass");

        tclass.setInterfaces(new CtClass[] {myinterface});



        return myinterface.toClass();








When I execute this code, since the ProxyIntAnAbstractClass is not interface of AnAbstractClass, InvocationHandler complains that the object is not an instance of declaring class


Can you please help me on this?