Jetty Maven Plugin - jetty:run does not work with pom type dependencies

[jaygarala]

Upgrading from Jetty 9.4 to 12

Jetty version(s)
Jetty 12

Jetty Environment
ee10

Java version/vendor (use: java -version)
OpenJDK 64-Bit Server VM (build 17.0.12+7-Ubuntu-1ubuntu222.04, mixed mode, sharing)
Apache Maven 3.6.3

OS type/version
Ubuntu 22

Description
This is working with Jetty 9.4. We have a maven dependency in the web-app that is <type>pom</type>, more details here. When running with jetty:run, we get the following error.

[INFO] jetty-12.0.12; built: 2024-07-25T21:58:37.668Z; git: cc6f1b74db755fed228b50701ad967aeaa68e83f; jvm 17.0.12+7-Ubuntu-1ubuntu222.04
[WARNING] Invalid Resource Reference: jar:file:/home/jay/.m2/repository/org/example/ext-maven-deps/1.0-SNAPSHOT/ext-maven-deps-1.0-SNAPSHOT.pom!/
[WARNING] Failed startup of context oeje10mp.MavenWebAppContext@6909f6be{ROOT,/,b=file:///home/jay/projects/temp/jetty-maven-proj/webapp/src/main/webapp/,a=STOPPED,h=oeje10s.SessionHandler@6b5ab2f2{STOPPED}}{file:///home/jay/projects/temp/jetty-maven-proj/webapp/src/main/webapp/}
java.lang.IllegalArgumentException: Unable to mount FileSystem from unsupported URI: jar:file:///home/jay/.m2/repository/org/example/ext-maven-deps/1.0-SNAPSHOT/ext-maven-deps-1.0-SNAPSHOT.pom!/
    at org.eclipse.jetty.util.resource.FileSystemPool.mount (FileSystemPool.java:135)
    at org.eclipse.jetty.util.resource.ResourceFactoryInternals$CompositeResourceFactory.mountIfNeeded (ResourceFactoryInternals.java:268)
    at org.eclipse.jetty.util.resource.ResourceFactoryInternals$CompositeResourceFactory.newResource (ResourceFactoryInternals.java:225)
    at org.eclipse.jetty.util.resource.ResourceFactoryInternals$Closeable.newResource (ResourceFactoryInternals.java:145)
    at org.eclipse.jetty.util.resource.ResourceFactory.newResource (ResourceFactory.java:331)
...
Caused by: java.nio.file.ProviderNotFoundException: Provider "jar" not found
    at java.nio.file.FileSystems.newFileSystem (FileSystems.java:359)
    at java.nio.file.FileSystems.newFileSystem (FileSystems.java:288)
    at org.eclipse.jetty.util.resource.FileSystemPool.mount (FileSystemPool.java:116)
    at org.eclipse.jetty.util.resource.ResourceFactoryInternals$CompositeResourceFactory.mountIfNeeded (ResourceFactoryInternals.java:268)
    at org.eclipse.jetty.util.resource.ResourceFactoryInternals$CompositeResourceFactory.newResource (ResourceFactoryInternals.java:225)
    at org.eclipse.jetty.util.resource.ResourceFactoryInternals$Closeable.newResource (ResourceFactoryInternals.java:145)
    at org.eclipse.jetty.util.resource.ResourceFactory.newResource (ResourceFactory.java:331)

How to reproduce?
Extract the sample project. Run mvn install, then cd webapp, and mvn jetty:run

jetty-maven-proj.zip

[joakime]

jetty-maven-plugin gets its dependencies directly from maven.
Maven is the one doing the resolution and handing it to the maven plugin.

[jaygarala]

Here is a similar sample project with Jetty 9.4
jetty9-maven-proj.zip

[janbartel]

@jaygarala thanks for the report. I've raised #12177 to fix it.

[olamy]

@jaygarala FYI using such dependency is deprecated in Maven, tend to generate some problems and might be removed in the coming Maven 4.
You should use a BOM strategy.
See this https://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html#bill-of-materials-bom-poms (as you can see the trick you are using is not even documented :)

[pzygielo]

(as you can see the trick you are using is not even documented :)

Seems exactly this to be documented in linked book by sonatype.

[olamy]

(as you can see the trick you are using is not even documented :)

Seems exactly this to be documented in linked book by sonatype.

sonatype != Apache Maven dev

btw that's probably outdated doc which need to be fixed.
@pzygielo what is the link?

[pzygielo]

In description, under more details here.

[olamy]

@pzygielo thanks.
so definitely not an official documentation from the Apache Maven project :)
anyway issue fixed, advice to use better practice.

[jaygarala]

@jaygarala FYI using such dependency is deprecated in Maven, tend to generate some problems and might be removed in the coming Maven 4. You should use a BOM strategy. See this https://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html#bill-of-materials-bom-poms (as you can see the trick you are using is not even documented :)

This is not a 'trick', it is documented here, known as Grouping Dependencies. You include the POM as your dependency and it will bring the declared dependencies into your project.

The BOM strategy is used to define the specific version of dependencies that you are including in the Maven module/sub-modules. You would still need to include the individual dependency in your module.

Also the issue is of a third-party dependency which we have no control over.

[olamy]

As said earlier you are reading some outdated documentation from a software vendor, this is not official documentation from the Apache Maven project.
Look at this page https://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html#bill-of-materials-bom-poms as you can see this trick is not even documented for good reason.

You would still need to include the individual dependency in your module.

Yes and this is a golden rule of using Maven always declare dependencies you are using if you want real control of your dependencies.
Do not rely on transitive dependencies as they can be change or worst adding a new dependencies can change all the tree and you may some dependencies/version you don't want.
Golden Rule again: you use a dependency declare it.

I'm saying with my hat of Maven developers to help you.
If you still have some doubt feel free to ask if it's a good practice on the user mailing list https://maven.apache.org/mailing-lists.html (I'm curious to see the answers :) )