In discussion on Git, someone said "Xalan-J currently does not use any logging frameworks."
That isn't quite correct. Xalan doesn't use one of the now-standard logging frameworks. But if you actually sift through the code, you'll find that most instances of System.err are either commented out, or behind debugging fences. Xalan has its own severity-level-filtered logging system, written when before those were generally adopted. (Actually, I suspect it has two; I haven't checked in as much detail but I believe xalan-test has its own, in the org.apache.qetest package hierarchy.) An additional detail to keep in mind when working on this code; Xalan's own messages run through an (equally early) i18n layer, supporting roughly 20 languages. When adding an error message, we really should be trying to run it through that system. It's simplest to use one of the message templates already there. If we really need a new message, we should look at adding a new -- /_ Joe Kesselman (he/him/his) -/ _) My Alexa skill for New Music/New Sounds fans: / https://www.amazon.com/dp/B09WJ3H657/ Caveat: Opinionated old geezer with overcompensated writer's block. May be redundant, verbose, prolix, sesquipedalian, didactic, officious, or redundant.