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Startup of the Java Instance

The following steps are involved in starting the Java instance:

1. JSTART is started (in Windows by the SAP Start Service; on UNIX platforms bythe startsap script). It takes the role of the Java instance controller.

2. The Java instance controller analyzes its configuration (from the instance profile)and examines the details of the Java SDK defined there.

3. The Java instance controller initializes SAP signal handling to be able to receivesignals and opens the control port.

4. The Java instance controller reads the instance description (from the list of filesspecified by the jstart/startupNodeFiles and jstart/instanceNodeFilesprofile parameters) for the first time, searching for nodes with a runLevel=1

property. The OFFLINE DEPLOYMENT node in the startup.properties file

matches this criterion.

5. The Java instance controller starts another JSTART process with the parametersfrom the OFFLINE DEPLOYMENT node and waits for the child process to

terminate.

6. The child process acts as a Java process. It loads the Java Virtual Machine (JVM)into its own process, initializes the JVM and starts the OFFLINE DEPLOYMENT

program, which performs the deployment steps in the Java database.

7. The Java instance controller reads the instance description again, searching fornodes with a runLevel=2 property. The BOOTSTRAP node in the

startup.properties file meets this condition.

8. The Java instance controller starts another JSTART process with the parametersfrom the BOOTSTRAP node and waits for the child process to terminate.

9. The child process loads and initializes the JVM and starts the BOOTSTRAPprogram. BOOTSTRAP synchronizes the binary data in the Java database with

the local file system, reads the Java instance description from the Java database

and updates the instance.properties file.

10.The Java instance controller reads the instance description from thestartup.properties and instance.properties files once more, this time

focusing on nodes with a runLevel=3 property or without a runLevel property atall. These nodes form the productive instance.

11.The Java instance controller starts the processes for infrastructure nodes, such asICM or DEBUGPROXY.

12.When all infrastructure processes are started, the Java instance controller starts theprocesses for the server nodes.

13.The JSTART child processes act as Java processes and execute a similar sequenceas described before. They become the Java server processes.

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An instance is stopped as follows:

1. A process (for example, the ABAP dispatcher, a start script or SAP Start Service)sends a SIGINT signal or an appropriate command to the Java instance controller.

2. The Java instance controller updates the instance state and sends STOPcommands to the server processes.3. When the server processes are finished, the Java instance controller sends STOPcommands to the infrastructure processes.

4. Once all child processes have exited, the Java instance controller terminates.