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  1. JDK
  2. JDK-4692504

TimeZone.getDefault() has too much synchronization

    Details

    • Type: Bug
    • Status: Resolved
    • Priority: P3
    • Resolution: Fixed
    • Affects Version/s: 1.3.1, 5.0
    • Fix Version/s: 5.0
    • Component/s: core-libs
    • Subcomponent:
    • Resolved In Build:
      tiger
    • CPU:
      generic, x86
    • OS:
      generic, windows_2000

      Backports

        Description



        Name: nt126004 Date: 05/28/2002


        FULL PRODUCT VERSION :
        Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.1_03-b03)
        Java HotSpot(TM) Client VM (build 1.3.1_03-b03, mixed mode)

        FULL OPERATING SYSTEM VERSION :

        Microsoft Windows 2000 [Version 5.00.2195]

        A DESCRIPTION OF THE PROBLEM :
        TimeZone.getDefault() is a static synchronzied method. In
        it the code checks to see if the default time zone has been
        initialized and if not initializes it. Once an initialized
        default is available it is cloned and returned to the
        caller. However the call to clone() need not be
        synchronized and causes uneeded contention.

        STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
        1. Write a multithreaded application which uses
        TimeZone.getDefault() (which many Date operations use).
        Get a profiler which can show you how much time you spend
        blocked trying to get the lock on TimeZone.class.
        2.
        3.

        This bug can be reproduced always.

        CUSTOMER WORKAROUND :
        Cache TimeZone.getDefault yourself in user code.
        Unfortunately this isn't always possible because in some
        cases the caller is also JDK or third party code.
        (Review ID: 146743)
        ======================================================================

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                • Assignee:
                  okutsu Masayoshi Okutsu
                  Reporter:
                  nthompsosunw Nathanael Thompson (Inactive)
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                    Updated:
                    Resolved:
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