JDK-6924259 : Remove String.count/String.offset/String.hashcode
  • Type: Enhancement
  • Status: Closed
  • Resolution: Fixed
  • Component: hotspot
  • Sub-Component: compiler
  • Priority: P3
  • Affected Version: hs17,1.4.0,5.0,6
  • OS: generic,windows_nt,windows_xp
  • CPU: generic,x86
  • Submit Date: 2010-02-08
  • Updated Date: 2017-05-16
  • Resolved Date: 2013-07-18
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JDK 7 JDK 8
7u6Fixed 8Resolved
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Description
Investigate the performance impacts of removing String.count, String.offset,
and String.hashcode on various industry standard benchmarks.
There are no new regression tests for this change because the API is not impacted. It is a behind-the-scenes performance/implementation change only

Comments
EVALUATION http://hg.openjdk.java.net/lambda/lambda/hotspot/rev/8f972594effc
2012-06-29

EVALUATION http://hg.openjdk.java.net/hsx/hotspot-rt/hotspot/rev/8f972594effc
2012-05-26

EVALUATION http://hg.openjdk.java.net/hsx/hsx23.2/hotspot/rev/3facbb14e873
2012-05-23

EVALUATION http://hg.openjdk.java.net/hsx/hotspot-comp/hotspot/rev/8f972594effc
2012-05-14

EVALUATION A working change has been developed that allows a version of the String class that doesn't use the count/offset fields. However, it's not possible to eliminate the hashcode field. This fix also works with compressed strings. At this point, the fix is on hold as other priorities have taken precedence.
2010-11-12