CICS reduces the number of active JVMs automatically if the workload does
not require them. If a JVM is inactive for 30 minutes, it is discarded.
You can terminate all the JVMs in the JVM pool by using a
CEMT SET JVMPOOL PHASEOUT, PURGE or FORCEPURGE command (or the equivalent
EXEC CICS command). When you use this command, all the JVMs in the pool, both
worker JVMs using the shared class cache and standalone JVMs running independently
of the shared class cache, are terminated. The shared class cache is also
terminated once all the worker JVMs that were dependent on it have been terminated.
On the CEMT SET JVMPOOL command:
- If you use the PHASEOUT option, the JVMs are marked for deletion, but
they are only terminated when they finish running their current Java programs.
- If you use the PURGE option, the tasks using JVMs are purged, and the
JVMs are terminated.
- If you use the FORCEPURGE option, the tasks using JVMs are forcepurged,
and the JVMs are terminated.
You can also disable the JVM pool so that it cannot service new requests,
by using a CEMT SET JVMPOOL DISABLED command (or
the equivalent EXEC CICS command). When you disable the JVM pool, the JVMs
in it are retained, but new Java programs cannot use them until you enable
the JVM pool again. Java programs that are already using a JVM are allowed
to finish running. To re-enable the JVM pool, use the CEMT SET JVMPOOL ENABLED
command (or the equivalent EXEC CICS command).