Why callback method is used for polymorphism

Question

I have a callback interface.

public interface CallBack{
  void executeforConn();
}

abstract class CallbackImpl implements Callback {     
  void executeforConn(){
    executeStatements();
  }

  abstract void executeStatements();
}

In the caller the callback is called.

new CallbackImpl{
  @Override
  executeStatements(){
    //extend the method
  }
}

Callback callback = new CallbackImpl();
callback.executeforConn();

The caller calls the implementation of callback method. What I do not understand why is it called a callback method. I know by using interface you get the flexibility to register any class which implements CallBack with the Caller. It doesn't have to be just CallBackImpl.

You are missing the `execute` in your instantiation of `CallbackImpl`. — Murat Karagöz, Aug 25 '17 at 12:44
Possible duplicate of [Polymorphism vs Overriding vs Overloading](https://stackoverflow.com/questions/154577/polymorphism-vs-overriding-vs-overloading) — Murat Karagöz, Aug 25 '17 at 12:47

Stephen C · Accepted Answer · 2017-08-25T13:04:45.010

What I do not understand why is it called a callback method.

It is called a "callback" because it allows the method that you passed the object to "call back" to your code.

For a more detailed explanation of the purpose and use of callbacks, read the Wikipedia article on callbacks.

Why callback method is used for polymorphism

A callback interface and (multiple) implementations could be viewed as a (rather uninteresting) example of polymorphism; e.g. one Callback API with multiple implementations that implement different behaviors.

Why callback method is used for polymorphism

1 Answers1