PermGen leak in GenericTypeResolver's typeVariableCache [SPR-5462]

[spring-projects-issues]

Wesley Hartford opened SPR-5462 and commented

I have a class SimpleXPathQueryCriteriaQueryGenerator extends AbstractSimpleCriteriaQueryGenerator<XPathQuery> implements XPathQueryCriteriaQueryGenerator. All four of these classes are loaded by the same URLClassLoader, which should be discarded at some point, all of spring is loaded by the parent ClassLoader, which stays around for a long time.

As far as I can tell, the org.springframework.core.GenericTypeResolver keeps a static WeakHashMap containing the SimpleXPathQueryCriteriaQueryGenerator as the key, and the XPathQuery contained in a map withing the value. The XPathQuery in the value results in a hard reference path back to the key of the WeakHashMap.

---

Affects: 2.5.5

[spring-projects-issues]

Wesley Hartford commented

The reference chain is essentially:

• [permenent class loader]
• class GenericTypeResolver
• WeakHashMap (key: class SimpleXPathQueryCriteriaQueryGenerator)
  • (value) HashMap
  • XPathQuery
  • [temporary class loader]
  • class SimpleXPathQueryCriteriaQueryGenerator

This causes a permanent reference path to the key in the weak hash map.

[spring-projects-issues]

Juergen Hoeller commented

This should be fixed in the upcoming 3.0 M3 release. We haven't fully researched the implications in terms of cache hits now, though (i.e. things still getting cached long enough).

Juergen