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mock exam question

 
Greenhorn
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hi can anybody please tell me whether this program will compile?



i think it will not compile becuase we can not add anything when we use the extends keyword
please correct me if i am wrong
 
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Did you try compiling the code? Of course compiler won't let you add anything. By <? extends Instrument> you are saying "I sware not to add anything to this list"

Regards.
 
Ranch Hand
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Vijitha wrote:

Of course compiler won't let you add anything

That's a common mistake. You can always add "null": allInstruments.add(null) compiles fine.
[ July 28, 2008: Message edited by: Ralph Jaus ]
 
Vijitha Kumara
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Sorry I forgot about it.you can add "null" there.
[ July 28, 2008: Message edited by: Vijitha Kumara ]
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