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From: Cecil Westerhof <Cecil@decebal.nl>
Newsgroups: comp.lang.java.programmer
Subject: Re: What goes wrong with cloning here
Date: Sat, 24 Oct 2015 00:51:22 +0200
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On Friday 23 Oct 2015 18:12 CEST, Tassilo Horn wrote:

> Cecil Westerhof <Cecil@decebal.nl> writes:
>
>> When I in class A change a field from class B in the clone, the
>> field in the original is also changed. That should not happen.
>>
>> public class A implements Cloneable {
>> 	private B key;
>> ^^^
>> 	public Object clone() throws CloneNotSupportedException {
>> 		A clone  = (A) super.clone();
>> 		B newKey = new B();
>> B oldKey = getKey();
>>
>> 		newKey.setA(oldKey.getA());
>> 		newKey.setB(oldKey.getB());
>> 		newKey.setC(oldKey.getC());
>> 		newKey.setD(oldKey.getD());
>> 		clone.setKey(key);
> ^^^
>
> I guess here you want to set the key of the clone to newKey, not to
> this.key.

Was an error in my dumbing down. :'-( In the original program it was
done correctly.


I found the problem. It is an application where the class is a JPA
class. When doing the test (in the original program) with an entity
that was gotten by a read it goes wrong. When doing it with an entity
gotten by a new it does what I expect.

Maybe it has to do with the fact that key is the primary key?

-- 
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof