Callback in Java

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package learncallback;

interface CallBack {
    void methodToCallBack();
}

class CallBackImpl implements CallBack {
    public void methodToCallBack() {
        System.out.println("I've been called back");
    }
}

class CallBackImpl1 implements CallBack {
    public void methodToCallBack() {
        System.out.println("Thieu Mao");
    }
}

class CallBackImpl2 implements CallBack {
    public void methodToCallBack() {
        System.out.println("Thieu Mao 2");
    }
}

public class LearnCallback {

    public void register(CallBack callback) {
        callback.methodToCallBack();
    }

    public static void main(String[] args) {
        LearnCallback caller = new LearnCallback();
        CallBack callBack = new CallBackImpl2();
        caller.register(callBack);
    }

}