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valid declarations

Giancarlo Yataco

Joined: Feb 01, 2009
Posts: 2
Hi Guys.
Lately I've been reading all about declarations in java and trying to resolve exercises about it.
I've been trying to figure out the answer of the following question but i still don't understand. The book says A , B and D are the answers. But why not C? and why D??

1.Which of the following are valid declarations? Assume java.util.* is imported.

A.Vector<Map> v;

B.Set<String> s;

C.Map<String> m;

D.Map<String, String> m;

Thanks in advance.
Balu Sadhasivam
Ranch Hand

Joined: Jan 01, 2009
Posts: 874

Welcome to Javaranch.
Since Map is an object that maps keys to values , The general declration of Map is Map<K,V> (keys, Values) Thats the reason D is true

Refer this
Campbell Ritchie

Joined: Oct 13, 2005
Posts: 46424
Welcome to JavaRanch

Please always when you post that sort of question, say where it comes from.
I agree. Here's the link:
subject: valid declarations
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