How does the updatePolicy in maven really work?
When I define an updatePolicy in my maven settings it tells maven how often snapshot artifacts shall be downloaded.
If I set it to always it of course downloads every time all snapshots.
I was wondering what happens if I set it to the default value daily or another longer peroid.
Does maven still check whether a new version of the snapshot is available and if so, does it download it although the policy says daily ?
I'm looking for the correct settings to avoid redundant downloads and not to miss a newer snapshot out there.
Answer
I was wondering what happens if I set it to the default value daily or another longer period.
The Repository - SNAPSHOT Handling explains it maybe better than the POM reference:
Each repository in the project has its own update policy:
- always - always check when Maven is started for newer versions of snapshots
- never - never check for newer remote versions. Once off manual updates can be performed.
- daily (default) - check on the first run of the day (local time)
- interval:XXX - check every XXX minutes
I don't think there is anything to add (except maybe that check != download).
Does maven still check whether a new version of the snapshot is available and if so, does it download it although the policy says daily ?
Well, no, why would it?
I'm looking for the correct settings to avoid redundant downloads and not to miss a newer snapshot out there.
Use always if you always want Maven to download a newer version of snapshots, if available (Maven will always check the remote repository but only download if the version is newer).