With the WebSphere Application Server for z/OS reliability, availability, and servicability support for Java (JRAS), you can issue messages from your Java application to the MVS master console. You might want to issue messages to the master console to report serious error conditions for mission-critical applications, or to trigger automation packages.
The messages your application issues also appear in either the error log stream or the component trace (CTRACE) data set that WebSphere Application Server for z/OS uses.
Logging the messages is another method of recording error conditions or collecting application data for diagnostic purposes.