Permgen Leak in JAXB due to recreation of JAXBContexts in CXF
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Key: CXF-2939
URL: https://issues.apache.org/jira/browse/CXF-2939
Project: CXF
Issue Type: Bug
Components: JAX-RS
Affects Versions: 2.1.5
Reporter: Stefan Schubert
>From
>http://cxf.547215.n5.nabble.com/REST-web-service-loading-many-classes-for-each-request-CXF-2-2-6-and-jaxb-impl-2-1-5-td2266472.html#a2266472:
If a GC occurs, WeakRefs throw away the JAXBContext. So on the next occasion
(where occasion could be one of billions of calls to a CXF/JAXB api) the
JAXBContext has to be rebuilt from scratch.
JAXB (specifically com.sun.xml.bind.v2.runtime.reflect.opt.AccessorInjector)
calls com.sun.xml.bind.v2.runtime.reflect.opt.Injector#find to try, if it
already created a field or method accessor class. If not it injects a new one
into the class loader via
com.sun.xml.bind.v2.runtime.reflect.opt.Injector#inject.
The problem is now that #inject caches the generated accessor in the Injector
and find only looks into the Injector (and never again into the class loader,
where it used to define the class). But once a GC occurs the Injector throws
itself away, too (caching itself in some weak map).
So it happens that each REST api call after a GC occurred a hundred new classes
are created by JAXB - because JAXB on low-level forgets the classes it defines
(and keeps them on high-level) and CXF forgets the JAXBContext so that the
high-level memory of JAXB is erased as well.
There are four possible solutions:
- Fix the Injector: Actually very easy and my favorite solution. Just let the
Injector look into the class loader as well when it cannot find the class in
its own memory. BUT to have a bug fixed in JAXB actually sounds scary, how long
would that take to get into a version?)
- Enable CXF to keep only one JAXB context (and not to throw it away) - do not
know how to do that
- Use a workaround to disable bytecode generation by JAXB
(-Dcom.sun.xml.bind.v2.bytecode.ClassTailor.noOptimize=true) --> disables the
whole bytecode magic Injector stuff and just does reflection - probably with a
slight performance impact
- Do not use JAXB with CXF on a website with significant load
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