Use case: You have an object with setListener, and you have to listeners. Do Combiner.combine(listener1, listener2), with any given type, and it'll do what you want

Combiner.java

package com.lacronicus.combodriver;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

/**
 * Created by fdoyle on 12/17/15.
 */
public class ListenerCombiner {
    public static <T> T combine(T arg, T... args) {

        InvocationHandler handler = new VarHandler(arg, args);
        return (T) Proxy.newProxyInstance(args[0].getClass().getClassLoader(),
                arg.getClass().getInterfaces(),
                handler);
    }

    static class VarHandler implements InvocationHandler {
        Object[] objects;
        Object object;

        public VarHandler(Object arg, Object... args) {
            this.objects = args;
            this.object = arg;
        }

        @Override
        public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
            Object firstReturnValue = method.invoke(object, args);
            for (Object object : objects) {
                method.invoke(object, args);
            }
            return firstReturnValue;
        }
    }
}

Usage.java

//both of these execute
        v.setOnClickListener(ListenerCombiner.combine(
                new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        Log.d("TAG", "first listener");
                    }
                },
                new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        Log.d("TAG", "second listener");
                    }
                }
        ));
        //this is not limited to click listeners. it will work with any type

Doesn't handle return values very well, but most android listeners don't really have those.

Maybe have a combine method for the return values?