The COBOL program suddenly terminates on the server and leaves thin client running with a blank screen

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If your program suddenly terminates on the server and leaves the thin client showing an empty window it can appear as if the application is hung.

The cause can be determined by setting the following properties when starting the isCOBOL Server:

iscobol.as.logging true
iscobol.as.logfile iscobolserver.log

Then examine the iscobolserver.log file for ERRORs or WARNINGs. For example:

WARNING: com.iscobol.rts.CommunicationException:
Communication exception:
com.iscobol.rmi.RemoteInvocationHandler$1:
 remote_exception sessionid 31510384 /sessionid class
java.lang.NoClassDefFoundError /class message
com/toedter/calendar/JSpinnerDateEditor /message
/remote_exception, prog 'MAIN_MENU'

In this example the WARNING shows that com.iscobol.rmi.RemoteInvocationHandler reports that the com.toedter.calendar.JSpinnerDateEditor class is not found.

If you see RemoteInvocationHandler and/or the word remote_exception it means that the warning or error occurs on the client. In this example the WARNING means that the jcalendar-1.3.2.jar file (which contains com.toedter.calendar.*) is not in the class path used when starting the thin client.