InvocationHandlerExample.java

public class HelloWorldInvocationHandler implements InvocationHandler {

    private final Object proxied;

    public HelloWorldInvocationHandler(Object proxied) {
        this.proxied = proxied;
    }

    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        System.out.println("Hello World");
        return method.invoke(proxied, args);
    }

}