Okay.  Is there an external way to send a running ecj process a message to
stop?

Here is an simple example of how I could do this:
I could have ecj poll periodically for a file named "stop.txt" on the
filesytem and if it exists, it would call Evolve.cleanup(state) and
System.exit(0).  Then anytime I want to stop ecj, I just create the stop
file and then delete it after ecj has stopped.

Is there currently a way to stop ecj using a similar technique or do I need
to implement this myself?  Also, if I need to do this myself, can you think
of a better way to do it than the example above?