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MustGather: Classloader problems for WebSphere Application Server


Technote (troubleshooting)


Problem(Abstract)

The following MustGather will assist you in setting up the traces and collecting the data required to analyze a classloader issue. This MustGather is needed to analyze exceptions such as:
ClassNotFoundException, NoClassDefFoundError, ClassCastException, NoSuchMethodError, LinkageError, UnsatisfiedLinkError, VerifyError, UnsupportedClassVersionError.

Resolving the problem

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The following MustGather will assist you in setting up the traces and collecting the data required to analyze a classloader issue. This MustGather is needed to analyze exceptions such as:

ClassNotFoundException, NoClassDefFoundError, ClassCastException, NoSuchMethodError, LinkageError, UnsatisfiedLinkError, VerifyError, UnsupportedClassVersionError.

To improve the accuracy of complete data collection, IBM recommends you use the automated data collectors within IBM Support Assistant. Not only will the automated collector gather the equivalent of the manual process, it will also provide a secure file transfer of the collection to IBM.

Collecting data using the IBM Support Assistant Data Collector

  1. Go to the ISA Data Collector site for WebSphere Application Server.

  2. Start the ISA Data Collector:
    • To run online, select the option to collect from this system using the current browser and click Start Collection.
    • To run locally, select the option to collect from this or another system using a downloadable utility. Download and extract the zip file to your WAS_HOME directory. From a command line, run isadc.[sh|bat] or launch index.html to use the web interface.

  3. Select the Runtime > Classloader Problem collector and click Start.

  4. Follow the prompts to automatically submit the collected data to IBM Support.

Collecting data manually



Perform the following steps to collect WebSphere Application Server specific information.

  1. Backup and clear all Application Server logs:

    native_stderr
    native_stdout
    SystemErr
    SystemOut


    The log files are located in the following directory:

    <profile_root>/logs/server_name/* 

    Clear all WebSphere Application Server FFDC logs. FFDC files are located in the following directory:

    <profile_root>/profile_name/logs/ffdc/*

    Note: If you have configured to write FFDC log files into a different location, then clear them accordingly.

  2. Enable and collect Application Server traces with the following trace string:

    com.ibm.ws.classloader.*=all

    For more details, see How to set up a trace.

  3. Enable Java™ Virtual Machine (JVM) classloader traces through the Admin console:

    1. Select Servers, choose Application servers and select the server you want to configure.

    2. In the Server Infrastructure section, open Java and Process Management and select Process Definition.

    3. Under Additional Properties, select Java Virtual Machine.

    4. Check the Verbose class loading checkbox.

    5. Add the following string to the Generic JVM arguments field:

      -Dws.ext.debug=true

    6. Click OK.

  4. Save the changes.

  5. Restart the server.

  6. Run the collector tool against the problem profile.

  7. Send IBM support the collector output, trace files and all the Application Server logs. Follow instructions to send diagnostic information to IBM support.


What to do next
Once you have collected the preceding information, send the diagnostic information to IBM support

Related information
Submitting information to IBM support
Steps to getting support for WebSphere Application Server
MustGather: Read first for WebSphere Application Server
Troubleshooting guide for WebSphere Application Server

Exchanging data with IBM Support

To diagnose or identify a problem, it is sometimes necessary to provide Technical Support with data and information from your system. In addition, Technical Support might also need to provide you with tools or utilities to be used in problem determination. You can submit files using one of following methods to help speed problem diagnosis:


Read first and related MustGathers

Cross reference information
Segment Product Component Platform Version Edition
Application Servers WebSphere Application Server - Express Java SDK AIX, HP-UX, Linux, Solaris, Windows 8.5, 8.0, 7.0, 6.1, 6.0
Application Servers Runtimes for Java Technology Java SDK

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Copyright and trademark information

IBM, the IBM logo and ibm.com are trademarks of International Business Machines Corp., registered in many jurisdictions worldwide. Other product and service names might be trademarks of IBM or other companies. A current list of IBM trademarks is available on the Web at "Copyright and trademark information" at www.ibm.com/legal/copytrade.shtml.

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Document information

WebSphere Application Server

Classloader


Software version:
6.0, 6.1, 7.0, 8.0, 8.5


Operating system(s):
AIX, HP-UX, Linux, Solaris, Windows


Software edition:
Base, Express, Network Deployment


Reference #:
1196187


Modified date:
2012-11-20

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