Groovy output from println statements, where is it?

[Kenny Cason]

I have some groovy code in a Jenkins pipeline that populates a dropdown chooser, sometimes.  The code calls a shell script which outputs a JSON string which is then parsed by Groovy to return just a list found in the JSON. When I run it standalone outside of Jenkins it always produces the correct JSON output I expect. When I run it inside Jenkins it works randomly.

I'd like to see the debug println output when the code doesn't work. Normally I would expect this to be in the Jenkins build console but there is no output from Groovy found there.

Does Groovy send sysout somewhere else, or can I force it to send it to a log?

(I would post the code but it's on a different server) :-(