cglib/src/main/java/net/sf/cglib/proxy/InterfaceMaker.java
public void add(Method method) {
        add(ReflectUtils.getSignature(method),
            ReflectUtils.getExceptionTypes(method));
    }
public void add(Method method) {
        add(ReflectUtils.getSignature(method),
            ReflectUtils.getExceptionTypes(method));
    }
Add a method signature to the interface. The method modifiers are ignored,
since interface methods are by definition abstract and public.
@param method the method to add to the interface