[FIXED] .getResource("/filename") returns null when maven packaging is pom

Issue

I have a Maven project with a submodule, developed in IntelliJ, using Java 11.

Unless the pom.xml file contains <packaging>pom</packaging>, there is a warning that

'packaging' with value 'jar' is invalid. Aggregator projects require 'pom' as packaging.

But when packaging is set to "pom", the resource file that I need can't be loaded; a null value is returned, and an exception is thrown. From the main() method:

    URL resource = getClass().getResource("/fx/gui.fxml");
    Objects.requireNonNull(resource);

On the other hand, sometimes the submodule is not found, unless I ask for pom packaging. What I do then is: Request pom packaging, start the program and watch it fail, remove the pom packaging statement from pom.xml, start again and the program works.

My resource file is in the standard location src/main/resources/fx/gui.fxml. This location is also given in the pom file:

<build>
    <sourceDirectory>${project.basedir}/src/main/java</sourceDirectory>
    <testSourceDirectory>${project.basedir}/src/test/java</testSourceDirectory>
    <resources>
        <resource>
            <directory>${project.basedir}/src/main/resources</directory>
        </resource>
    </resources>
</build>

Please help me understand what's going on. Do I need pom packaging, and how can resources be loaded with it?

Solution

Looks like you have your source code in your parent pom.

A parent pom (with sub-modules) must have packaging as pom and cannot have java source code. See this question

You should move your code in a new sub-module.

Answered By - Zinc
Answer Checked By - Willingham (JavaFixing Volunteer)