z/OS problem determination

This section describes problem determination on z/OS®.

Setting up and checking your z/OS environment
Set up the correct environment for the z/OS VM to run correctly.
General debugging techniques
A short guide to the diagnostic tools provided by the JVM and the z/OS commands that can be useful when diagnosing problems with the z/OS JVM.
Diagnosing crashes
A crash should occur only because of a fault in the JVM, or because of a fault in native (JNI) code that is being run inside the Java™ process. A crash is more strictly defined on z/OS as a program check that is handled by z/OS UNIX as an unrecoverable signal (for example, SIGSEGV for PIC4; 10, 11, or SIGILL for PIC1).
Debugging hangs
A hang refers to a process that is still present, but has become unresponsive.
Understanding Memory Usage
To debug memory leaks, you need to understand the mechanisms that can cause memory problems, how the JVM uses the LE HEAP, how the JVM uses z/OS virtual storage, and the possible causes of a java.lang.OutOfMemoryError exception.
Debugging performance problems on z/OS
Locating the causes of poor performance is often difficult. Although many factors can affect performance, the overall effect is generally perceived as poor response time or slow execution of your program.
MustGather information for z/OS
The more information that you can collect about a problem, the easier it is to diagnose that problem. A large set of data can be collected, although some is relevant to particular problems.

Parent topic: Problem determination