Generics and cloning

[Sreedevi Vinod]

hi

When I try to compile the following code, I get warnings about the unchecked cast used for the return type of the clone method. How do
I rectify this ?

 HashSet<String> l=new HashSet<String>();
 l.add("AB");
 l.add("BC");
 l.add("BC");
 Set<String> s=(Set<String> ) (l.clone());  

Thanks
Devi

[ May 22, 2005: Message edited by: Sreedevi Vinod ]
[ May 22, 2005: Message edited by: Barry Gaunt ]

[Sreedevi Vinod]

hi how do I remove the smily from my post above ?
[ May 22, 2005: Message edited by: Sreedevi Vinod ]

[Barry Gaunt]

Smiley?

There's a disable smiley check box at the bottom of the form in which you enter your code. You may have to scroll down a bit though. Or you can add space between the offending characters.

Oh now I see it's because of the > and ) being close together.
I'll fix it.
[ May 22, 2005: Message edited by: Barry Gaunt ]

[Tony Morris]

import java.util.*;
 
class X
{
{
HashSet<String> l=new HashSet<String>(); 
l.add("AB"); 
l.add("BC"); 
l.add("BC"); 
Set<?> s=(Set<?>)l.clone();
}
}

The Cloneable interface is arguably the most broken (I can think of only one other candidate) part of the core J2SE API. It always has been. Since the introduction of JSR14, it is even more (but only slightly in comparison) broken. You can either:
a) put up with it and therefore, put up with its extreme shortcomings.
b) do it properly (it doesn't offer you much anyway).

Cloning an object itself (regardless of the broken API) requires an obscure case justification because it is almost certainly unnecessary. If you insist on cloning an object (for a justified reasoning or not), you can simply do something like (disclaimer: off the top of my head with no real thought):

// We can spell it differently (since there is no such word as 'cloneable' or 'clonable')
// without fear of a clash with the broken one in java.lang.
interface Clonable<T> 
{
T getClone();
}

(Edit: disabled smilies)
[ May 22, 2005: Message edited by: Tony Morris ]