JVM trace

JVM trace can aid in the diagnosis of problems in the Java Virtual Machine (JVM). Note that JVM trace can produce a large amount of output, so you should normally activate JVM trace for special transactions, rather than turning it on globally for all transactions.

Controlling tracing for JVMs tells you about the different ways to activate JVM tracing and change the JVM trace options. To summarize, you can control JVM trace using: The first two methods, using CETR and using the CICS system initialization parameters, are most similar to the methods that you would use to define tracing for other components.

When you set trace levels 29–32 for the SJ component and activate JVM trace, each JVM trace point that is generated appears as an instance of CICS trace point SJ 4D01. If the JVM trace facility fails, CICS issues the trace point SJ 4D00.

In addition to the JVM trace options, the standard trace points for the SJ (JVM) domain, at CICS trace levels 0, 1 and 2, can be used to trace the actions that CICS takes in setting up and managing JVMs and the shared class cache. The SJ domain includes a level 2 trace point SJ 0224, which shows you a history of the programs that have used each JVM. “JVM domain trace points” in CICS® Trace Entries has details of all the standard trace points in the SJ domain.