Message9985

So the relevant line of code is the subprocess.call in https://github.com/jythontools/jython/blob/master/src/shell/jython.py#L435:
 try:
 result = subprocess.call(command)
 if args.help:
 print_help()
 except KeyboardInterrupt:
 pass
This should be more robust, catching any runtime error and re-wrapping. One possibility is for it to attempt diagnosis: is java/jdb available? Were there other issues that were raised?
Clearly you have Java installed somewhere to do the installation, but you may have to fix up with JAVA_HOME in this particular case.