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GC, strange question!

 
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#181 The presence of a mapping for a given key withinthis collection instance will not prevent the keyfrom being recycled by the garbage collector.

Which concrete class provides the specified features?

(1) Vector
(2) Hashtable
(3) TreeMap
(4) TreeSet
(5) HashMap
(6) HashSet
(7) WeakHashMap
(8) None of the above




Please Help!

I am not able, how to interpret this question!

Regards,
cmbhatt
 
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I think the answer is WeakHashMap because I read

"A hashtable-based Map implementation with weak keys. An entry in a WeakHashMap will automatically be removed when its key is no longer in ordinary use. More precisely, the presence of a mapping for a given key will not prevent the key from being discarded by the garbage collector, that is, made finalizable, finalized, and then reclaimed. When a key has been discarded its entry is effectively removed from the map, so this class behaves somewhat differently than other Map implementations. "

Am I correct?
 
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Am I correct?



yah , WeakHashMap is the correct answer because

its remove keys that no longer used and make them available for GC
 
Chandra Bhatt
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What the heck are you genuine ranchers are talking about?

COULD ANYBODY PLEASE GIVE ME A LITTLE EXAMPLE OF THAT???
Henry, Barry where are you?







Regards,
cmbhatt
 
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It looks like the other guys used the Java API or read the tutorial
[ April 22, 2007: Message edited by: Barry Gaunt ]
 
Chandra Bhatt
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Straight from the Java API tutorial:


WeakHashMap is an implementation of the Map interface that stores only weak references to its keys. Storing only weak references allows a key-value pair to be garbage-collected when its key is no longer referenced outside of the WeakHashMap. This class provides the easiest way to harness the power of weak references. It is useful for implementing "registry-like" data structures, where the utility of an entry vanishes when its key is no longer reachable by any thread.



What are weak references?
What I understood and what I did is as following:

 
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