Java Startup and Control Framework


The Java startup and control framework comprises the programs JControl and Jlaunch. JLaunch is started by JControl and itself starts the bootstrap Java program or an element of the Java cluster (dispatcher or server process).


The Java startup and control framework is used to start, stop, and monitor a Java Instance.

The program JControl starts the Java instance as specified in the configuration file.


The framework consists of the following components:

·        JControl starts, stops, and monitors the processes of a Java instance (usually a dispatcher and several server processes). The program implements the SAP signal handling to stop the instance. JControl starts the JLaunch processes.

·        JLaunch starts a Java program. It loads the JVM into its own address space and then represents the required cluster element. The program can receive notification from the JControl process via named pipes to stop the cluster element, and terminates, if the JControl stops running (fork emulation under Windows).

·        The Bootstrap JAVA program synchronizes the binary data from the Java database with the local file system and creates a property file, which describes the processes of the Java instance.

The process is described in Startup, Operation and Shutdown of a Java Instance.


The Java startup and control framework is called in different ways according to the operating system and installation type:

·        Under Windows, the SAP Management Console is used. If you choose Action ® Start from the context menu of an instance containing a J2EE Engine, the JControl program is called.

·        Under UNIX and OS/400 platforms, the scripts startsap and stopsap are used to call the JControl program.

·        If you start the Java instance using the SAP NetWeaver Developer Studio (NWDS), the client integrated into the NWDS calls the JControl programJControl.

See also:

Starting and Stopping the SAP System (UNIX)

Starting and Stopping the SAP System (Windows)