Creating the instance of abstract class or anonymous class

Question

In this code here is it creating the object of abstract class or anonymous class? Please tell me. I am little bit confused here.

public abstract class AbstractDemo {

    abstract void showMessage();
    abstract int add(int x,int y);

    public int mul(int x,int y){
        return x+y;
    }


    public static void main(String[] args) {
        AbstractDemo ad = new AbstractDemo() {

            @Override
            void showMessage() {
                // TODO Auto-generated method stub

            }

            @Override
            int add(int x, int y) {
                // TODO Auto-generated method stub
                return 0;
            }
        };

        System.out.println(ad.mul(10, 12));
        System.out.println(ad.getClass());
    }

}

Answer 1

You create an anonymous class that extends your abstract class.

In the snipped below, you are extending AbstractDemo and provide implementations for its abstract methods.

new AbstractDemo() {
    @Override
    void showMessage() {
        // TODO Auto-generated method stub
    }

    @Override
    int add(int x, int y) {
        // TODO Auto-generated method stub
        return 0;
    }
};

Answer 2

Here's what happened in this short and innocent piece of code:

AbstractDemo ad = new AbstractDemo() {

            @Override
            void showMessage() {
                // TODO Auto-generated method stub

            }

            @Override
            int add(int x, int y) {
                // TODO Auto-generated method stub
                return 0;
            }
        };

1. New class was defined (without a name, so called anonymous class)
2. This new class extends AbstractDemo class
3. Abstract methods of AbstractDemo were overriden in this new class
4. New instance of this new class was created and assigned to ad variable

Read more about anonymous classes in Java here.