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  1. JDK
  2. JDK-4493940

HPROF: Some objects in heap dump have no referrers (no objects reference them )

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    • Subcomponent:
    • CPU:
      generic
    • OS:
      generic

      Description

      Java(TM) 2 Runtime Environment, Standard Edition (build
      1.4.0-beta_refresh-b72)
      Java HotSpot(TM) Client VM (build 1.4.0-beta_refresh-b72, mixed mode)

      Run hprof against on any simple class (HelloWorld.java) and analyze the heap dump. You will find that some objects in the heap dump have no referrers at all. When I say that some objects have no referrers, I mean that there are no objects in the heap dump referencing them. My understanding is that the heap dump should only contain live objects, therefore all objects should have at least one reference to them.

      Profiling a simple "Hello World" Java program will illustrate the problem.
      I've also attached output from hprof that illustrates the problem. There
      are quite a few objects in the attached dump that have no referrers. For
      example, look at objects:

      8c3ee70
      96ddc0
      8c44618
      8c92440
      8ba1448

      There is no object in the heap dump referencing them. There are more
      objects with no referrers; these are just a few.

      Tested with the latest build 76 (merlin-beta2 release) to see if fix for 4363856 will address this issue, but the problem still exists.

      I have noticed that it's often (but not always) String objects that do not have any references to them.

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              • Assignee:
                ohair Kelly Ohair (Inactive)
                Reporter:
                rverabel Raghu Verabelli (Inactive)
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