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All About Reference Objects |
The Reference objects API defines strengths of object reachability. There can be (going from strongest to weakest) softly, weakly and phantomly reachable objects and gain an amount of interaction with the garbage collector according to the strength of an object's reachability.There is no limit to the number or type of references there can be to an object. One object can be referenced by any mix of strong, soft, weak, and phantom references depending on your application requirements.
To determine an object's strength of reachability, the garbage collector starts at the root set and traces all the paths to objects on the heap. The reference objects that the garbage collector goes through to reach an object are what determine the reachability of that object. When all paths to an object are free of reference objects, the object is strongly reachable. When one or more paths have one or more reference objects, the object is softly, weakly, or phantomly reachable according to the type of reference object(s) the garbage collector finds. In general, an object is only as reachable as the weakest link in the strongest path from the root set. The sections to follow describe how this all works.
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All About Reference Objects |