confused in overriding question

[Mark Guo]

 class Parent {
	public void show(Parent p) {
		System.out.println("Parent");
	}
}
 
public class Chat extends Parent{
	 public void show(Chat p) {
			System.out.println("Chat");
	 }
	 
	 public static void main(String[] args) {
		Parent p = new Chat();
		Chat c = new Chat();
		p.show(c);
	}
 }

Why the answer is "Parent" rather than "Chat"

[Christophe Verré]

Please QuoteYourSources.

Why the answer is "Parent" rather than "Chat"

The answer to what question ?

[Mark Guo]

My question is Why the answer is "Parent" rather than "Chat"???

[Christophe Verré]

The answer to what question ? You are copy/pasting some code, and telling what the answer is, but there's no question.

And you still didn't tell us where this question came from.

[Bharath Raja]

first clear me your class name which contains main method is "Chat" or "Chat1"...? If two are different, then where is your "Chat" class.

[Mark Guo]

I mean the out put is "Parent" not "Chat" why?

[Abimaran Kugathasan]

Still there is a typo on 7th line, and QuoteYourSources

[Abimaran Kugathasan]

Then if I asked, why you are expecting Chat as the output?

[Hrishikesh Yeshwant Alshi]

This is overloading in disguise of overriding. (In case if one is not clear with the rules of overriding). I mean, the method show() in the Chat class is NOT overridden. It is overloaded.

Rule is: An overriding method must have argument lists of IDENTICAL type and order.

Let us elaborate,

1. order is out of question here as there is only one argument.
2. type must be IDENTICAL, this means IDENTICAL. "IS A" is not permitted.

Try compiling the below code which has just one change. I have added @Override annotation to the Chat class's show method. This annotation ensures that the method is ACTUALLY overridden. This means, suppose if developer intended to actually override the method from the super class but mistakenly he missed something and ended up in overloading it then his friend "@Override" annotation will help him by finding his slip EARLY (at compile time).

It is a good practice to use annotation in your code. They are your friends.

class Parent {  
	public void show(Parent p) {  
		System.out.println("Parent");  
	}	  
}  

public class Chat extends Parent{  
	
	
	@Override public void show(Chat p) {  
		System.out.println("Chat");  
	}  

	public static void main(String[] args) {  
		Parent p = new Chat();  
		Chat c = new Chat();  
		p.show(c);  
	}  
}  

By adding the annotation @Override to this code it will not even compile and it will tell the developer that the method is NOT correctly overridden as it violated the above stated rule.

[Mark Guo]

Thanks Hrishikesh Yeshwant Alshi, thanks for your time and patience.

[Christophe Verré]

You still didn't quote your sources. Where does this code come from ?

[Mark Guo]

Hi Hrishikesh Yeshwant Alshi the code should be

class Parent {    
    public void show(Parent p) {    
        System.out.println("Parent");    
    }       
}    
  
public class Chat extends Parent{    
      
      
    @Override 
    public void show(Parent p) {    
        System.out.println("Chat");    
    }    
  
    public static void main(String[] args) {    
        Parent p = new Chat();    
        Chat c = new Chat();    
        p.show(c);    
    }    
}  

the parameter should as same as Parent.

[Abimaran Kugathasan]

And, you don't need the @Override annotation here.

[Hrishikesh Yeshwant Alshi]

Hi Hrishikesh Yeshwant Alshi the code should be

Yes you are right. The code I have posted won't compile because the method in the show() method of Chat class is not correctly overridden.

And, you don't need the @Override annotation here.

We still need it. It's always recommended to have annotations in your code. Imagine during maintenance someone trying to change the show() method in Chat class. Our friend "@Override" will be there to report the mistakes (if any).

ALWAYS have "@Override" annotation in your code when you are intending to override any method.

[Hrishikesh Yeshwant Alshi]

Hi Hrishikesh Yeshwant Alshi the code should be

Yes you are right. The code I have posted won't compile because the method in the show() method of Chat class is not correctly overridden.

And, you don't need the @Override annotation here.

We still need it. It's always recommended to have annotations in your code. Imagine during maintenance someone trying to change the show() method in Chat class. Our friend "@Override" will be there to report the mistakes (if any).

ALWAYS have "@Override" annotation in your code when you are intending to override any method.

[Harikrishna Gorrepati]

class Parent {
    public void show(Parent p) {
	System.out.println("Parent");
    }
}

public class Chat extends Parent {
    public void show(Parent p) {
	System.out.println("Parent in chat class");
    }

    public void show(Chat p) {
	System.out.println("Chat");
    }

    public static void main(String[] args) {
	Parent p = new Chat();
	Chat c = new Chat();
	p.show(c);
    }
}

Now the output is, Parent in chat class. What I have given is method overriding. So, it uses object type.
Your program is an example of Overloading. It uses reference type.