JDK-8003820 : Deprecate untested and rarely used GC combinations
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: gc
  • Affected Version: hs25
  • Priority: P3
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2012-11-21
  • Updated: 2017-05-17
  • Resolved: 2013-01-04
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JDK 8 Other
8Fixed hs25Fixed
Related Reports
Relates :  
JDK-8005396 - Use ParNew with only one thread instead of DefNew as default for CMS on single CPU machines
Relates :  
JDK-8039566 - Remove GC combinations deprecated in JDK 8
Relates :  
JDK-8006398 - Add regression tests for deprectated GCs
Description
The GC combinations ParNew + SerialOld and DefNew + CMS are very rarely used. There are no use cases that we know of where these are superior to other GC combinations.

We are currently not doing active testing on these combinations.

To simplify the GC combination matrix and make sure that we have resources to test all GC combinations that we support we would like to remove these two combinations. The plan is to deprecate these combinations in JDK8 and remove them in JDK9.
Comments
Suggested release note: The GC combinations ParNew + SerialOld and DefNew + CMS have been deprecated and will likely be removed in a future release. It is recommended to use ParallelScavenge + SerialOld instead of ParNew + SerialOld and to use ParNew + CMS instead of DefNew + CMS.
08-01-2013