Note: This article applies from release version 5.3 SP2 through release version 5.4 SP3. This issue is resolved in Version 5.5.
The message NoClassDefFoundError displays when you run an activity that includes hand-crafted Java and that uses a third-party .jar file. Your application server is IBM WebSphere Application Server, Version 5.1.1, 6.0.1, 6.0.2, or 6.1. Although you have included the .jar file in the shared library and referenced it in your application, the classloader fails to load the .jar file.
Using the IBM WebSphere Application Server Administrative Console, add the .jar file to the WebSphere Application Server classpath. Refer to the IBM WebSphere Application Server information center for the version that your application environment is using.