Mvn error updating group repository metadata
This can be useful if you have one job that triggers on all patch set created events that just checks that the commit message is correctly formatted, so it should only deny merging if it is a bad commit message but also not allow the merge just because the message was ok.
In that scenario you could configure the "check commit message" job to skip voting on Successful.
If your Jenkins instance has been down for a period of time (upgrade or maintenance), the Missed Events Playback Feature ensures that any missed events are re-played and builds are triggered.
By checking the checkbox "Dynamic Trigger Configuration", the user is asked for the URL to a file.
On a set interval, the plugin fetches and parses this file.
There are many more settings for your pleasure, look at the individual help sections for information what they are about.
In the "Build Triggers" section of your Job configuration page; tick "Gerrit event": Specify what Gerrit project(s) to trigger a build on.
If this does not work for you set Refspec to refs/changes/*:refs/changes/* and 'Branches to build' to $GERRIT_REFSPEC.