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Message:

Copy constructors

Posted by Martin Maisey on 12 Oct 1998, 7:55 AM

> I believe that all classes should support a copy constructor:

> public void someMethod (Foo fIsaFoo) {
> Foo barIsAnotherFoo = new Foo(fIsaFoo);
> ....
> }

I'm not sure this is necessary - as far as I can see, a copy constructor doesn't provide any different semantics from clone(), so why provide it? It's not needed for by-value parameter passing as in C++, as this feature isn't supported in Java.

This is covered in Thinking in Java by Bruce Eckel, IMHO one of the best Java books out there. Read it for a better explanation than I could ever give.

Martin