CJSA was introduced in CICS® Transaction Server for z/OS®, Version 5 Release 1 for JVM servers. It is the default transaction to start CICS tasks that run new threads in the JVM server for a Java™ application. You can override it using a URIMAP resource.
CJSA is defined in the CICS-supplied resource definition group DFHJAVA. The JVM server has a listener that runs as a long-running task. The listener runs the CJSA transaction to create CICS tasks when an application requests a new thread. These threads can use JCICS to access CICS services.
CJSA is a RACF® category 2 transaction.