How to get notified of updates to public maven repositories for new plugins?
There is now an excellent site: https://www.artifact-listener.org/
Maven Versions Plugin
Not an automatic solution but you can use the Maven Versions Plugin has a versions:display-plugin-updates goal that will check all the plugins and reports used in your project and display a list of those plugins with newer versions available. Here is an example of the output it produces:
[INFO] ------------------------------------------------------------------------
[INFO] Building Unnamed - org.codehaus.mojo.versions-maven-plugin.it:parent:pom:2.0
[INFO] task-segment: [versions:display-plugin-updates]
[INFO] ------------------------------------------------------------------------
[INFO] [versions:display-plugin-updates]
[INFO]
[INFO] The following plugin updates are available:
[INFO] maven-checkstyle-plugin .................................. 2.1 -> 2.2
[INFO] maven-clean-plugin ....................................... 2.1 -> 2.2
[INFO] maven-deploy-plugin ...................................... 2.3 -> 2.4
[INFO] maven-javadoc-plugin ..................................... 2.4 -> 2.5
[INFO] maven-site-plugin .......................... 2.0-beta-6 -> 2.0-beta-7
[INFO]
[WARNING] The following plugins do not have their version specified:
[WARNING] maven-compiler-plugin ..................... (from super-pom) 2.0.2
[WARNING] maven-deploy-plugin ......................... (from super-pom) 2.3
[WARNING] maven-install-plugin ........................ (from super-pom) 2.2
[WARNING] maven-javadoc-plugin ........................ (from super-pom) 2.4
[WARNING] maven-site-plugin .................... (from super-pom) 2.0-beta-6
[WARNING] org.codehaus.mojo:build-helper-maven-plugin .................. 1.2
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESSFUL
[INFO] ------------------------------------------------------------------------
[INFO] Total time: < 1 second
[INFO] Finished at: Mon Sep 01 15:55:18 IST 2008
[INFO] Final Memory: 6M/104M
[INFO] ------------------------------------------------------------------------
It can also be used to produce a report (part of the site) that you could for example generate each night.
I was not necessarily looking for updates on the libraries used in my project, but was interested in obtaining regular updates on certain products which I am interested in.
For this, the best option might be to subscribe to the relevant mailing lists (by mail or RSS) and to track announcements.