Uploaded image for project: 'JDK'
  1. JDK
  2. JDK-4646747

Wrong getPersistenceDelegate() return after memory stress

    XMLWordPrintable

    Details

    • Type: Bug
    • Status: Resolved
    • Priority: P3
    • Resolution: Fixed
    • Affects Version/s: 1.4.0
    • Fix Version/s: 1.4.1
    • Component/s: client-libs
    • Labels:
    • Subcomponent:
    • Resolved In Build:
      hopper
    • CPU:
      x86
    • OS:
      windows_2000

      Description



      Name: nt126004 Date: 03/04/2002


      FULL PRODUCT VERSION :
      java version "1.4.0"
      Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-b92)
      Java HotSpot(TM) Client VM (build 1.4.0-b92, mixed mode)

      FULL OPERATING SYSTEM VERSION :
      Microsoft Windows 2000 [Version 5.00.2195]



      A DESCRIPTION OF THE PROBLEM :
      XMLEncoder looses custom PersistenceDelegate after
      intensive memory allocation. It works as expected under
      1.4.0beta3 but fails on 1.4.0RC1.
      In the provided test program, I create new 1MB array in
      loop and check whether or not getPersistenceDelegate()
      returns the same object, i've put by
      setPersistenceDelegate() earlier.
      Test output shows, that:
      1. on 1.4.0RC1 check fails after third allocation. (because
      JVM starts by default with 2M memory pool)
      2. on 1.4.0Beta3 check is OK on 10 allocations.



      STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
      1.Compile provided class.

      2.Run test:

      java persistence_test.Test



      EXPECTED VERSUS ACTUAL BEHAVIOR :
      Output on 1.4.0RC1:
      Before memory allocation: OK
      0 OK
      1 OK
      2 Different: persistence_test.Test$1 :
      java.beans.DefaultPersistenceDelegate
      Test finished

      Output on 1.4.0beta3:
      Before memory allocation: OK
      0 OK
      1 OK
      2 OK
      3 OK
      4 OK
      5 OK
      6 OK
      7 OK
      8 OK
      9 OK
      Test finished

      Note:

      The actual results would depend on how many memory JVM
      allocated on startup on your system...


      This bug can be reproduced always.

      ---------- BEGIN SOURCE ----------
      package persistence_test;

      import java.beans.*;
      import java.io.*;


      public class PersistenceTest {

         
          public static void main(String[] args){
              final int ARRAYSIZE = 1000000;
              final int BUFERLENGTH = 10;
              
              try{
                  XMLEncoder encoder = new XMLEncoder(new BufferedOutputStream(new
      ByteArrayOutputStream()));
                  PersistenceDelegate pd = new DefaultPersistenceDelegate(){
                      protected Expression instantiate(Object oldInstance, Encoder
      out) {
                          return super.instantiate(oldInstance, out);
                      }
                      protected void initialize(Class type, Object oldInstance,
      Object newInstance, Encoder out) {
                          super.initialize(type, oldInstance, newInstance, out);
                      }
                  };
                  encoder.setPersistenceDelegate(Test.class, pd);
                  Object[] bufArray = new Object[BUFERLENGTH];
                  System.out.print("Before memory allocation: ");
                  checkClasses(pd, encoder.getPersistenceDelegate(Test.class));
                  for(int i=0; i < BUFERLENGTH; i++){
                      bufArray[i] = new byte[ARRAYSIZE];
                      System.out.print(i + " ");
                      if (checkClasses(pd, encoder.getPersistenceDelegate
      (Test.class))) break;
                  }
                  encoder.close();
                  System.out.println("Test finished");
              }catch(Exception ex){
                  ex.printStackTrace();
              }
          }
          
          public static boolean checkClasses(PersistenceDelegate pd1,
      PersistenceDelegate pd2){
              if (pd1 == pd2)
                  System.out.println("OK");
              else{
                  System.out.println("Different: " + pd1.getClass().getName()
      + " : " + pd2.getClass().getName());
              }
              return pd1 != pd2;
          }
      }


      ---------- END SOURCE ----------

      CUSTOMER WORKAROUND :
      The possible ugly work around is increasing JVM startup
      memory amount with -Xms key.
      (Review ID: 139123)
      ======================================================================

        Attachments

          Issue Links

            Activity

              People

              Assignee:
              mdavidsosunw Mark Davidson (Inactive)
              Reporter:
              nthompsosunw Nathanael Thompson (Inactive)
              Votes:
              0 Vote for this issue
              Watchers:
              0 Start watching this issue

                Dates

                Created:
                Updated:
                Resolved:
                Imported:
                Indexed: