Restarting the J2EE Engine: Checking the JLaunch-Trace 
You can easily call the JLaunch traces using the SAPMMC by selecting a process in the process list and choosing Developer Trace using the context menu.
Dispatchers and servers are started by JLaunch processes. The start has run correctly if status 3 is reached:
JLaunchISetState: change state from 2 to 3.
Additional Information
For information about the start of the individual processes of the J2EE Engine, see the relevant JLaunch trace, in which the numbers of the message server ports, P4 ports, debug ports, and so on are listed.
For more information about JLaunch, see the Administration Manual under Startup, Operation and Shutdown of a Java Instance.