Details
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Type:
Bug
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Status:
Closed
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Priority:
Critical
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Resolution: Fixed
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Affects Version/s: 1.3.1
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Fix Version/s: 1.4
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Component/s: Converters
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Labels:None
Description
This has been discussed in XSTR-395 however it hasn't been dealt with satisfactorily IMO.
Due to the default StringConverters use of a cache (even if it is a WeakHashMap), if a single instance of the XStream class is used over a long period to serialise many thousands of objects then eventually an OutOfMemoryError will occur. This is due to a new WeakHashMap#Entry being added to the cache for every new string inside each of serialised objects.
IMO this is very dangerous and should NOT be the default behaviour. I understand that many people use XStream in many different ways but surely this pitfall should be avoided in the default configuration. If you need to cache strings for performance then you should install a CachingStringConverter rather than the other way around.
It took me longer than it should have to track down this OOM error as I was (perhaps foolishly?) assuming that XStream release version 1.3.1 would be rock solid.
Issue Links
- supercedes
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XSTR-410
Fix for issue 395 also causes OutOfMemoryError
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Activity
Hi,
I am using XStream version 1.3.1. Still I faced this problem of java.lang.OutOfMemoryError: PermGen space. Has this issue been resolved completely or does this still persist.
Few lines of exception:
Exception in thread "DemandGen-JobStatusPollerThread" java.lang.OutOfMemoryError: PermGen space
at java.lang.String.intern(Native Method)
at com.thoughtworks.xstream.converters.basic.StringConverter.fromString (StringConverter.java:19)
I am creating single instance of XStream which is being used for long and my use case relates to different strings each time, thus caching is not at all important.
Would using non caching version of StringConverter or creating new instance of XStream solve this problem ?
Thanks
Jitendra
added a comment - Hi,
I am using XStream version 1.3.1. Still I faced this problem of java.lang.OutOfMemoryError: PermGen space. Has this issue been resolved completely or does this still persist.
Few lines of exception:
Exception in thread "DemandGen-JobStatusPollerThread" java.lang.OutOfMemoryError: PermGen space
at java.lang.String.intern(Native Method)
at com.thoughtworks.xstream.converters.basic.StringConverter.fromString (StringConverter.java:19)
I am creating single instance of XStream which is being used for long and my use case relates to different strings each time, thus caching is not at all important.
Would using non caching version of StringConverter or creating new instance of XStream solve this problem ?
Thanks @Jitendra: You're definitely not using XStream 1.3.1. However, the user's list is the appropriate place for discussion.
Jörg Schaible
added a comment - @Jitendra: You're definitely not using XStream 1.3.1. However, the user's list is the appropriate place for discussion. Hi,
I was wandering where can I find NonCachingStringConverter ? Do I need to write it on my own?
Bartosz Bulczyński
added a comment - Hi,
I was wandering where can I find NonCachingStringConverter ? Do I need to write it on my own? @Bartosz: Currently, yes. It's more that trivial.
Jörg Schaible
added a comment - @Bartosz: Currently, yes. It's more that trivial. The StringConverter has a constructor taking a map that can be used for the cache. Upcoming XStream version will support a null value as parameter value to turn off the cache completely.
Jörg Schaible
added a comment - The StringConverter has a constructor taking a map that can be used for the cache. Upcoming XStream version will support a null value as parameter value to turn off the cache completely. 
Opps - let me just correct two mistakes that I made above.
1) It was discussed in
XSTR-410rather than the originalXSTR-395.2) An OOME might not actually happen... but the JVM will grind to a halt and spend most of it's time doing FULL GC's.