Deep Copying Error

Question

Dea All,

I have the following:

class test {
    int x = 6;
    int y = 7;

    private int getX() {
        return x;
    }

    private int getY() {
        return y;
    }

    public test copy() {
        test myTest = new test();
        myTest.x = getX();
        myTest.y = getY();
        return myTest;
    }
}

However, when I then execute:

test a = new test();
test b = a.copy();
b.x = 17;
System.out.println(a.x);

The result is still 17. However, shouldn't deep copying prevent this?

Anybody who can help me?

It is really hard to help you when you ask "Why does my code do X?", when in fact it does **not** do X. — NPE, Mar 21 '13 at 22:16

NPE · Answer 1 · 2013-03-21T22:15:12.023

3

First of all, you are ignoring the return value of b.copy() in:

test b = new test();
b.copy();

Secondly, I've tested your code and it prints 6 and not 17 as you say in the question.

edit I notice that you've fixed the first issue in an edit. However, the code still doesn't behave the way you say it does.

edited Mar 21 '13 at 22:15

answered Mar 21 '13 at 22:00

NPE

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Third: that isn't even deep copy ;-) – ITroubs Mar 21 '13 at 22:01
@ITroubs: I was going to say something about this, but then decided it was deep *enough* ;) – NPE Mar 21 '13 at 22:02
Yeah, the last edit he made to the post fixes the bug and it now returns 17. It didn't originally have the same code. – Marvo Mar 21 '13 at 22:07

score 0 · Answer 2 · answered Mar 21 '13 at 22:09

0

The result should be 6 not 17.

answered Mar 21 '13 at 22:09

sowrov

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Deep Copying Error

2 Answers2