in startsap/stopsap command line executable , the ... - BeKnowledge

Details on the Framework
• SAP provides a separate Startup and Control Framework for SAP Web Application
Server Java. This Framework is used to start, stop, and monitor the Java stack
processes within the SAP system instances - but not, however, the Central
Services.It consists of the following processes:
• JControl:
– JControl starts, stops, and monitors the processes of a Java instance . Primarily
the server and dispatcher processes. SAP Signal Handling is implemented with
JControl, to forward the start and stop commands to the processes of the Java
stack.
– JControl restarts terminated processes, ends hanging processes, and sends a
shutdown signal to the processes of the Java stack.
– JControl reads the description of the instance from profile files.
– JControl starts the JLaunch processes, which in turn start Java nodes such as
dispatchers or servers.
– JControl creates a shared memory segment for the internal administration data
of all JLaunch processes.
• JLaunch:
– JLaunch starts a Java program, loads a Java VM (JVM) in its own address
space and assumes the function of the corresponding cluster element. The
parameterizing of the JVM is read before the loading.
– JLaunch receives commands from the JControl process (through named pipes)
to stop cluster elements such as dispatchers or servers.
– The JLaunch process ends itself if its parent process JControl is no longer
running.
18 October 2010