使用超级关键字覆盖方法

Question

I have one doubt, Please see the following code. i have three classes A , B and InheritanceExample . Here I am calling the super.run() from the main class; it is calling the B class run() method.

Is there any option to call A class run method from the main class ( InheritanceExample ) with out creating an instance for class A?

class A
{
    void run()
    {
        System.out.println("<<<====Class A run Method===>>>>");
    }
}

class B extends A
{
    void run()
    {

        System.out.println("<<<====Class B run Method===>>>>");
        super.run();
    }
}

public class InheritanceExample extends B{

    /**
     * @param args
     */
    void run()
    {
        System.out.println("<<<====Main Class run Method===>>>>");
        super.run();
    }
public static void main(String[] args) {
    InheritanceExample a = new InheritanceExample();
    a.run();
} 
    }

Answer 1

Since B extends A and InheritanceExample extends B you are creating an instance. Make method A.run() static .

class A
{
    void static run()
    {
        System.out.println("<<<====Class A run Method===>>>>");
    }
}

class B
{
    void run()
    {
        System.out.println("<<<====Class B run Method===>>>>");
        A.run();
    }
}

public class InheritanceExample extends B {

    @Override
    void run()
    {
        System.out.println("<<<====Main Class run Method===>>>>");
        super.run();
    }

    public static void main(String[] args) {
        InheritanceExample a = new InheritanceExample();
        a.run();
    } 
}

Answer 2

No.

Not without making A.run() different from B.run(), such as by making A.run() static.

When B extends A, you as a programmer must ensure that from the callers perspective B "is-a" A. What you want to do is to break this rule.

If you want to use a B as an A, you are probably trying to do something at the calling point, that should be handled internally in B.

Answer 3

Not sure what you want to achieve. But looking at the class hierarchy and structure, it is not possible to directly call run method of Class A. But if we change and introduce a additional static method say runImpl in Class A, and call same method from run method of Class A. Now we can call runImpl from anywhere as it is static and run method too internally is calling runImpl so same implementation is getting call via run and runImpl.

Below is the code snippet:

class A
{
    void run()
    {   
        runImpl();
    }

    public static void runImpl(){
        System.out.println("<<<====Class A run Method===>>>>");
    }
}

class B extends A
{
    void run()
    {

        System.out.println("<<<====Class B run Method===>>>>");
        super.run();
    }   

}

public class InheritanceExample extends B{

    /**
     * @param args
     */
    void run()
    {
        System.out.println("<<<====Main Class run Method===>>>>");
        super.run();
    }
    public static void main(String[] args) {
        A.runImpl();
    } 
}

Answer 4

  class a{

      void run(){

          System.out.println("runing method run of a clss");

      }
  }
  class b extends a{
      void run(){
          super.run();
          System.out.println("runing method run of b clss");
      }

  }
  class InheritanceExample extends b{
      void run(){
          super.run();
          System.out.println("running method run in inheritance class");
      }
  }

  class pratics{
      public static void main(String[] args){
        System.out.println("********");
        InheritanceExample a1=new InheritanceExample();
        a1.run();
       System.out.println("********");
      }
  }