valid declarations

[Giancarlo Yataco]

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]

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]

Welcome to JavaRanch

Please always when you post that sort of question, say where it comes from.