Fix (APAR):  PQ80782

Status:  Test

Release:  5.1.0,5.0.2.2,5.0.2.1,5.0.2

Operating System:  N/A

Supersedes Fixes:  

CMVC Defect:  182106

Byte size of APAR:  7722

Date: 2003-12-01

Abstract:  A NullPointerException or ConcurrentModificationException is thrown from either the SelectionManager or PMIManager during very heavy workloads

Description/symptom of problem:  Under heavy workloads, a NullPointerException or ConcurrentModificationException is thrown from a WeakHashmap object in the Workload Management code.  The exception may look something like this:

Root exception is java.util.ConcurrentModificationException: 
concurrent access to HashMap attempted by Thread Thread-7,5, 
at java.util.HashMap.onExit(HashMap.java:175) 
at java.util.HashMap.rehash(HashMap.java:347) 
at java.util.HashMap.put(HashMap.java:418) 
at java.util.WeakHashMap.put(WeakHashMap.java:298) 
at com.ibm.ws.wlm.client.selection.SelectionManager.pushServerForInvocat 
at com.ibm.ws.wlm.client.selection.SelectionManager.getTarget(SelectionM 
...
...


Directions to apply fix:  

NOTE:  YOU MUST FIRST DOWNLOAD THE UPDATE INSTALLER TOOL IN ORDER TO INSTALL A FIX.
       The Fix Installer can be downloaded from the following link:
       http://www-3.ibm.com/software/webservers/appserv/support/index.html

1) Create temporary "fix" directory to store the jar file:
             UNIX: /tmp/WebSphere/fix
          Windows: c:\temp\WebSphere\fix

2) Copy jar file to the directory

3) Shutdown WebSphere

4) Follow the Fix installation instructions that are packaged with the Fix Installer on how to install the Fix.

5) Restart WebSphere

6) The temp directory may be removed.

Directions to remove fix:  
NOTE:  FIXES MUST BE REMOVED IN THE ORDER THEY WERE APPLIED.  DO NOT REMOVE A FIX UNLESS
     ALL FIXES APPLIED AFTER IT HAVE FIRST BEEN REMOVED.  YOU MAY REAPPLY ANY REMOVED FIX.

Example:  If your system has fix1, fix2, and fix3 applied in that order and fix2 is to be
          removed, fix3 must be removed first, fix2 removed, and fix3 re-applied.


1) Shutdown WebSphere

2) Follow the instructions that are packaged with the Fix Installer on how to uninstall the Fix.

3) Restart WebSphere

Directions to re-apply fix:  
1) Shutdown WebSphere

2) Follow the Fix instructions that are packaged with the Fix Installer on how to uninstall and reinstall the Fix.

3) Restart WebSphere



Additional Information: