this=null What will happen.

[Ankur Sharma]

Isn't it ambiguious solution this program is giving could anyone explain me what is happening here in this code. Attached is the code.

public class Sample {
public static void main(String[] args) {
Sample sam = new Sample();
sam.add();
}
public void add() {
this = null;
}
}

[Jayesh Lalwani]

My compiler gives an error while compiling that line. It says "cannot assign a value to final variable this"

[Jeff Albertson]

I see no ambiguity.

[faisal usmani]

Originally posted by Jayesh Lalwani:
My compiler gives an error while compiling that line. It says "cannot assign a value to final variable this"

Mine too!!!

[faisal usmani]

Originally posted by Jeff Albertson:
I see no ambiguity.

In what sense ?

[Keith Lynn]

I agree with Jeff. What is the ambiguity?

[faisal usmani]

I think , this should not be assigned 'null' . correct me if i am wrong


regards

[Keith Lynn]

No it should not be assigned to null. Based on the message the compiler gives, this is a final variable associated with the class and like other final variables, it cannot be assigned a new value. But that isn't ambiguous.

[Ilja Preuss]

If I remember correctly, an early version of the Eclipse compiler didn't flag assignment to "this" as an error. I don't remember whether that was a bug, or something that actually officially changed with later Java versions...

[Ilja Preuss]

Found the bug report: https://bugs.eclipse.org/bugs/show_bug.cgi?id=38143

[Ankur Sharma]

Actually It's compiling finely. But I don't understand if we are assigning current object to null then how it's going to System.out.println() is working. Please let me clearify.

[Jesper de Jong]

Actually It's compiling finely

On which Java version? Did you see what the people above are saying about Eclipse? Are you using Eclipse? Eclipse has its own built-in Java compiler. According to the bug report above, there's a bug in Eclipse that allows you to assign a value to "this". It shouldn't be possible.

It's not interesting to find out why it still works - it's an illegal Java program and the behaviour is undefined. You noticed that the System.out.println() still works, but it just as well could not have worked. What the program does, is undefined. It could do anything. It could even make your hair turn purple.
[ April 06, 2006: Message edited by: Jesper de Jong ]

[Ilja Preuss]

Originally posted by Ankur Sharma:
Actually It's compiling finely.

That's the bug. It shouldn't.

[Riya Pant]

<br>I tried this on WSAD which is running java 1.4.<br>Compiler is giving error "The left-hand side of assignment must be a variable"