This paper discusses application server crashes that are related to the Java Virtual Machine (JVM ) or Just In Time (JIT) compilers in WebSphere Application Server V6. A problem in these components is normally fatal to the application server and can cause it to crash.

High-level symptoms of issues with these components that are most often reported by users are:

- The application appears to be hung or not available, and the application is not responding to incoming requests.

- The performance of the application is degrading.

If the application server process is gone from the system or if the process ID is constantly changing (the application server is being restarted), you are probably experiencing an application server crash.

This paper applies to WebSphere Application Server V6 for distributed systems only. It does not cover WebSphere Application Server for z/OS.