I realized that i made some mistake in the snippet provided in the last report. First the getClassLoader() method should be called on the same class where the snippet has been included (my.wrapper.Controller). Then the metaclass argument in makeReflective() invocation should be javassist.tools.reflect.ClassMetaobject.
Doing this way I can intercept the methods of any class but not of abstract classes, which is my case. Nobody knows how I can make this!?