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A '''soft reference''' is a reference that is garbage-collected less aggressively. The soft reference is one of the strengths or levels of 'non [[strong reference|strong]]' reference defined in the [[Java (programming language)|Java programming language]], the others being [[weak reference|weak]] and [[phantom reference|phantom]]. In order from strongest to weakest, they are: strong, ''soft,'' weak, phantom.

Soft references behave almost identically to weak references. Soft and weak references provide two quasi-priorities for non-strongly referenced objects: the [[Garbage collection (computer science)|garbage collector]] will always collect weakly referenced objects, but will only collect softly referenced objects when its algorithms decide that memory is low enough to warrant it.

Soft references may be used, for example, to write a free memory sensitive [[cache (computing)|cache]] such that cached objects are kept until there is not enough heap space. In some cases weakly referenced objects may be reclaimed too quickly to make such a cache useful.

== See also ==
* [[Circular reference]]
* [[Phantom reference]]
* [[Weak reference]]

== External links ==
* [http://www.pawlan.com/monica/articles/refobjs/ Java developer article: 'Reference Objects and Garbage Collection']
* {{cite web |last=Nicholas |first=Ethan |url=http://weblogs.java.net/blog/2006/05/04/understanding-weak-references |title=Understanding Weak References |publisher=java.net |date=May 4, 2006 |accessdate=October 1, 2010 |url-status=dead |archiveurl=https://web.archive.org/web/20100819115659/http://weblogs.java.net/blog/2006/05/04/understanding-weak-references |archivedate=August 19, 2010 }}

[[Category:Data types]]
[[Category:Memory management]]

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