[opencms-dev] Null Pointer in CmsFlexCacheEntry

[Nick Panienski]

Hi,

we have a problem with "random" 500 errors in a production environment. We are using a clustered OpenCms (6.5.6) with the OCEE package installed. First we could not find any stack traces (!!) in the logs, but reading the Java 5 release notes revealed the following:

"... the compiler may choose a faster tactic using preallocated exceptions that do not provide a stack trace. To disable completely the use of preallocated exceptions, use this new flag: -XX:-OmitStackTraceInFastThrow."

Enabling this feature for the HotSpot VM resulted in stack traces (w00t!). Every time the "random" error occurs it's the CmsFlexCacheEntry class that throws a null pointer exception at line 352:

  // write output to stream and process all included elements
  for (int i = 0; i < m_elements.size(); i++) {

I did not dig into the FlexCache yet to figure out what causes m_elements to be null, can anyone think of a scenario where this happens and maybe provide a solution for this?

Any help appreciated!
Nick

--
Mit freundlichen Grüßen
Nick Panienski
Senior IT Consultant

codecentric GmbH
Grünewalder Str. 29-31
42657 Solingen

Telefon  +49 (212)  24 94 330
Fax      +49 (212)  24 94 334
Mobil    +49 (151) 167 06 496
eMail    panienski at codecentric.de
Internet http://www.codecentric.de

Geschäftsführer: Peter Gierse, Mirko Novakovic und Rainer Vehns Sitz der Gesellschaft: Solingen
Registergericht: Amtsgericht Wuppertal, HRB 19214