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I am Java EE developer but I don't know where in day to day programming one might use Weak or Soft references.

Arjan Tijms
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  • Here is a very good blog post on this very topic: http://weblogs.java.net/blog/2006/05/04/understanding-weak-references I think it will help clear your confusion. – Hunter McMillen Dec 06 '11 at 03:55
  • This SO question will be helpful. [http://stackoverflow.com/questions/299659/what-is-the-difference-between-a-soft-reference-and-a-weak-reference-in-java][1] [1]: http://stackoverflow.com/questions/299659/what-is-the-difference-between-a-soft-reference-and-a-weak-reference-in-java – Upul Bandara Dec 06 '11 at 03:56

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You don't not normally use them in day to day programming (at least i don't and i think most of us don't) but they can be very useful!

practical scenarios for me would be:

WeakReference for debugging purpose (e.g. keep track of open database connections).

SoftReference for a quick and dirty cache (e.g. caching large java POJOs that are "expensive" to create and should not be cleaned up immediately).

PhantomReference is really impracticable in my opinion.

Philipp Sander
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There are many good references (nice pun!) and I suggest you Google Bob Lee, "the ghost in the virtual machine."

In a nutshell, a SoftReference is occasionally useful as a quick and dirty cache, but they aren,t that useful. WeakRefences are not for caching, but your listener lists should definitely use them so that unneeded listeners can be garbage collected.

user949300
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