OpenLiberty maven plugin & EAR project: Ignored exclusions of transitive dependencies in ear.xml

Setup

Maven EAR project
OpenLiberty plugin for local test deployment in a Liberty server

Behaviour of the plugin

The plugin deploys an XML file which aggregates a list and links to required runtime jars, instead of building an EAR file -- so far, so good, the application starts and runs.

Issue

However, some dependencies in the project have colliding transitive dependencies and the pom.xml contains a lot of exclusions. Unfortunately, those exlusions are ignored by the plugin and the application encounters runtime issues due to the aformentioned clashes (ClassNotFoundException etc.). Those -- of course -- do not occur, if one drops in the EAR file.

Questions

Is there a possibility to fix this issue and make the *.ear.xml contain those exclusions?
If not, is there a possibility to explicitly make the plugin build and use the EAR artifact instead of the implicitly generated xml file?

Solution

Bypassing "loose application" and generating a normal archive file

To answer one part of your question, you can configure the liberty-maven-plugin to deploy the full binary archive (WAR or EAR) rather than use the XML-defined representation via the <looseApplication>false</looseApplication> parameter on your liberty-maven-plugin configuration:

    <build>
        <plugins>
            <plugin>
                <groupId>io.openliberty.tools</groupId>
                <artifactId>liberty-maven-plugin</artifactId>
                <version>3.9</version>
                <configuration>
                    <looseApplication>true</looseApplication>
            ...

This will be less convenient for iterative development, since you have to do a full "package" and then another "deploy" rather than only having to do another "compile", but it would be a way to work around the issue you discovered.

Follow-up

As far as the issue with the liberty-maven-plugin not handling exclusions in building the loose application XML file, I suggest opening an issue in the liberty-maven-plugin GitHub repo (https://github.com/OpenLiberty/ci.maven/) and I'll update this when we have one.