IIUC, I don't think this works. URLClassLoader that's responsible for loading classes from the plugin doesn't have any parent, so if plugin classes refer to classes in Hudson core, for example, then those references will fail to resolve.

A bit more compact implementation of the child-first classloader, as a result of my looking at the patch. For the reason I put in my earlier comment, this doesn't really work either.

here an other proposal.
This works here with a maven3-plugin.
If you want I can checkin this last one (but it's a very POC and very in PROGRESS work ).

From some mail traffic on hudson-dev I guess that it's a blocker to the issue I opened for Maven 3 compatibility.

I think also this Bug is a blocker.

After the maven 3.0. beta1 release more and more developer would switch.

Please check it.

The proposed patch doesn't make sense to me — that is, PluginFirstClassLoader is not doing anything useful, because its child URLClassLoader and its "2nd parent" URLClassLoader has the exact same content, the former always load everything that the latter can load. Plus you still have the same problem of the 2nd URLClassLoader not having any parent.

I don't think you can create a child-first classloader by delegating to another URLClassLoader. You really need your own URLClassLoader-like implementation (for example AntClassLoader might be a good start) that does child-first.

Code changed in hudson
User: : olamy
Path:
trunk/hudson/tools/maven-hpi-plugin/src/main/java/org/jvnet/hudson/maven/plugins/hpi/AbstractHpiMojo.java
http://jenkins-ci.org/commit/33086
Log:
adding a new Manifest entry to be able to play with JENKINS-5360

here a new patch.
A work in progress (or POC which needs a lot of more jobs regarding maven 3 in hudson is here : http://github.com/olamy/hudson-maven3-support

a patch with more help methods (getURLs returning jars)

Code changed in hudson
User: : olamy
Path:
trunk/hudson/main/core/pom.xml
trunk/hudson/main/core/src/main/java/hudson/ClassicPluginStrategy.java
trunk/hudson/main/core/src/main/java/hudson/PluginFirstClassLoader.java
trunk/hudson/main/core/src/main/java/hudson/security/Permission.java
http://jenkins-ci.org/commit/35076
Log:
JENKINS-5360 add a new classloader ("a la" child first for plugin)

Code changed in hudson
User: : olamy
Path:
trunk/www/changelog.html
http://jenkins-ci.org/commit/35077
Log:
JENKINS-5360 update changelog

Integrated in hudson_main_trunk #287
JENKINS-5360 add a new classloader ("a la" child first for plugin)

olamy :
Files :

• /trunk/hudson/main/core/src/main/java/hudson/security/Permission.java
• /trunk/hudson/main/core/pom.xml
• /trunk/hudson/main/core/src/main/java/hudson/PluginFirstClassLoader.java
• /trunk/hudson/main/core/src/main/java/hudson/ClassicPluginStrategy.java