The Jython script doesn't have access to the environment variables that are
documented. Things like WORKSPACE and BUILD_TAG would be useful. Here's what
print(os.environ) outputs now for me:

{'ALLUSERSPROFILE': 'C:\\Documents and Settings\\All Users', 'TMP': 'C:\\WINDOWS\\TEMP', 'PROCESSOR_ARCHITECTURE': 'x86', 'WINDIR': 'C:\\WINDOWS', 'PROCESSOR_REVISION': '0208', 'PROCESSOR_LEVEL': '15', 'PATHEXT': '.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH', 'COMPUTERNAME': 'IPTAPPS-RYAN1', 'PROGRAMFILES': 'C:\\Program Files', 'BASE': 'C:\\Hudson', 'FP_NO_HOST_CHECK': 'NO', 'COMSPEC': 'C:\\WINDOWS\\system32\\cmd.exe', 'USERPROFILE': 'C:\\Documents and Settings\\Default User', 'SYSTEMDRIVE': 'C:', 'OS': 'Windows_NT', 'TEMP': 'C:\\WINDOWS\\TEMP', 'SYSTEMROOT': 'C:\\WINDOWS', 'CLUSTERLOG': 'C:\\WINDOWS\\Cluster\\cluster.log', 'NUMBER_OF_PROCESSORS': '1', 'PROCESSOR_IDENTIFIER': 'x86 Family 15 Model 2 Stepping 8, GenuineIntel', 'PATH': 'C:\\WINDOWS\\system32;C:\\WINDOWS;C:\\WINDOWS\\System32\\Wbem', 'HUDSON_HOME': 'C:\\Hudson', 'COMMONPROGRAMFILES': 'C:\\Program Files\\Common Files'}