At last some daylight -
My login.jsp had misspelled field names! j_user_name instead of j_username. Since I copied this from another working application, I never thought to look at it. Now login module is being found.
File this for future reference!
That explains why there was a 'null' in the log for username - i couldn't find an explanation for that when i was looking at your stuff, i'll remember it now ;-).
Cheers,
Peter
How does one submit a patch or enhancement request for Jetty? Two awful days of headscratching seems like an awfully steep price to pay for my sin, such as it was. I think silent failure in this case is inappropriate - a log file entry should be made in a case like this.