方法不会在Java中从其超类重写方法

Question

I have the above title error message on my override methods. I've followed this pubnub tutorial to try and get a working example and can't figure out why I'm getting these messages. The only difference is I'm using intellij. Here's the tutorial in case it helps.

Here's my code:

import com.pubnub.api.*;
import com.sun.org.apache.xpath.internal.operations.String;

public class SubscribePublishExample {

    //Creating an instance of pubnub and adding the subscribe code.
    public void subscribePublish() {
        final Pubnub pubnub = new Pubnub("demo", "demo");

        try {
            pubnub.subscribe("Hell0 World", new Callback() {

                @Override
                public void successCallback(String arg0, Object arg1) {
                    System.out.println(arg1);
                }

                //Adding the publish code into the connect callback.
                @Override
                public void connectCallback(String arg0, Object arg1) {
                    pubnub.publish("Hello_World", "Hello World !", new Callback() {
                        @Override
                        public void successCallback(String arg0, Object arg1) {
                            System.out.println(arg1);
                        }
                    });


                }
            });
        } catch (PubnubException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        new SubscribePublishExample().subscribePublish();
    }
}

Answer 1

I'm assuming Callback is an interface. Based on the first time you implement it (when you pass it to pubnub.subscribe() ) using an abstract class instance, it has two methods - successCallback() and connectCallback() .

However, inside your connectCallback() implementation, you have another abstract class instance implementing Callback (which you pass to pubnub.publish() ), and this time you forgot to implement connectCallback() .

    pubnub.subscribe("Hell0 World", new Callback()
    {

        @Override
        public void successCallback(String arg0, Object arg1)
        {
            System.out.println(arg1);
        }
        //Adding the publish code into the connect callback.
        @Override
        public void connectCallback(String arg0, Object arg1)
        {
            pubnub.publish("Hello_World", "Hello World !", new Callback()
            {
                @Override
                public void successCallback(String arg0, Object arg1)
                {
                    System.out.println(arg1);
                }

                // here you should add an implementation of connectCallback :
                @Override
                public void connectCallback(String arg0, Object arg1)
                {
                    // some code
                }
            });


        }
    });