Overriding problem

[Nancy Antony]

Hi Ranchers,

See the code below

import java.io.IOException;
import java.io.FileNotFoundException;
import java.sql.SQLException;
class OverLoadOrOverRideParent1 {

	void show6() throws IOException{
				System.out.println("Hi from show6 Parent");
				throw new ArithmeticException();
	}
}

class OverLoadOrOverRideChild1 extends OverLoadOrOverRideParent1 {
                  void show6() {
				System.out.println("Hi from show6 Child");
				throw new IOException();
	}
}

class OverLoadOrOverRideDemo1 {
	public static  void main(String [] args){
		OverLoadOrOverRideChild1 ob = new OverLoadOrOverRideChild1();
	                OverLoadOrOverRideParent1 p; //1
		p=ob;//2
		ob.show6();//3
		p=new OverLoadOrOverRideChild1(); //4/
		p.show6(); //5
	}
}

If I comment lines 4 and 5 it calls the show6() of child class
But when I include lines 4 and 5 it gives compile time error unreported exception

Now my confusion is when parent refers the child object which is already created, it runs fine. But when I create Child Object and on the left parent object ref is present then it gives error. Why?

Regards,
Nancy

(Jesper Young: Added code tags - please click the link to learn about code tags and how to use them).

[Vijitha Kumara]

Please use code tags. Un-formatted code is hard to read.

[Nancy Antony]

what are code tags?

[Vijitha Kumara]

First go to the edit screen () and then in the edit page use the button "Code" to include all your code inside it.

[Treimin Clark]

Nancy Antony wrote:what are code tags?

Look at the below example on using code tags:

class M{
     public void init(){
     }
}

When typing posting a code fragment, please use the "Code" button to let it to be rendered as a 'code'. And see it is important to use code tags.

[Nancy Antony]

Thanks for explaining

I've posted it once again using code tag.

[Hemnathbabu Kottaiveedu]

Hi Nancy,

Are you sure that your code compiled when you commented the lines 4 and 5? It did not compile fine when I tried to do it.

It gave an error saying that the show6() method in the child class must throw IOException or it must be caught. After commenting the line throw new IOException(); your code compiled fine.

Now when the lines 4 and 5 are uncommented then there you are trying to implement polymorphism which is a runtime phenomenon. So at compile time the Parent class show6() method is referred and hence the compiler gives the error.

To compile that code you need to put the p.show6() code in a try catch block or declare the main method as throwing the IOException.

Hope this helps you.

Thanks,
Hemnath

[Vijitha Kumara]

I've posted it once again using code tag.

Where? It's not edited in your original post. Or somewhere else?

[Jesper de Jong]

You don't need to repost the whole question just to add code tags. You can edit your own posts by clicking the button on the top right of your post.

I added the code tags for you (I can do that because I'm a moderator in this forum).

I see your repost is here. Please continue there, I'm closing this topic.