I found an NPE while trying to monitor an external process as described here:

• https://hudson.dev.java.net/cron.html
  *
  http://hudson.gotdns.com/wiki/display/JENKINS/Monitoring+external+jobs#Monitoringexternaljobs-Monitoringcronjobs

example batch file:
{{{
#!/bin/sh

echo "hello"
}}}

(after copying graph-layouter-1.0-jdk14.jar, servlet-api-2.4.jar to the same dir
as hudson-core-1.136.jar...)

output from run:
{{{
$ java -jar hudson-core-1.136.jar "import" hello.sh
Sep 6, 2007 6:07:35 PM hudson.TcpSlaveAgentListener <init>
INFO: JNLP slave agent listener started on TCP port 40260
Sep 6, 2007 6:07:36 PM hudson.model.Hudson load
INFO: Took 192 ms to load
java.lang.NullPointerException
at hudson.model.ExternalJob.newBuild(ExternalJob.java:47)
at hudson.Main.localPost(Main.java:70)
at hudson.Main.run(Main.java:49)
at hudson.Main.main(Main.java:32)
}}}

I'm not sure which 'Subcomponent' this issue belongs to either... looking for
something like 'main/core/' but didn't find it.