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

public class DemoProxy {
	public static void main(String[] args) {
		Class iface = DemoProxyFunction.class;
		ClassLoader loader = DemoProxyFunction.class.getClassLoader();
		InvocationHandler handler = new SomeHandler();
		DemoProxyFunction function = (DemoProxyFunction) Proxy.newProxyInstance(loader, new Class[] { iface }, handler);
		System.out.println("output value " + function.evaluate(5, 10));
	}

	static class SomeHandler implements InvocationHandler {
		public Object invoke(Object arg0, Method method, Object[] args) throws Throwable {
			if ((Integer.class.equals(method.getReturnType()))
				&& (args.length == 2)
				&& (args[0] instanceof Integer)
				&& (args[1] instanceof Integer))
				return null;
			int value1 = ((Integer) args[0]).intValue();
			int value2 = ((Integer) args[1]).intValue();
			return new Integer(value1 + value2);
		}
	}
}