Question about WeakHashMap
- by michael
Hi,
In the Javadoc of "http://java.sun.com/j2se/1.4.2/docs/api/java/util/WeakHashMap.html", it said
"Each key object in a WeakHashMap is
stored indirectly as the referent of a
weak reference. Therefore a key will
automatically be removed only after
the weak references to it, both inside
and outside of the map, have been
cleared by the garbage collector."
And then
Note that a value object may refer
indirectly to its key via the
WeakHashMap itself; that is, a value
object may strongly refer to some
other key object whose associated
value object, in turn, strongly refers
to the key of the first value object.
But should not both Key and Value should be used weak reference in WeakHashMap?
i.e. if there is low on memory, GC will free the memory held by the value object (since the value object most likely take up more memory than key object in most cases)?
And if GC free the Value object, the Key Object can be free as well?
Basically, I am looking for a HashMap which will reduce memory usage when there is low memory (GC collects the value and key objects if necessary).
Is it possible in Java?
Thank you.
