[MJAR-292] Detect MRJAR and add manifest entry

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.3.0
• Fix Version/s: 3.4.0
• Assignee: Slawomir Jaranowski
• Reporter: Jorge Solórzano
• Created: 19/Dec/22 17:22
• Updated: 29/Mar/24 16:44
• Resolved: 26/Jan/23 17:26

Description

With the aim of reducing boilerplate, the maven-jar-plugin should be able to autodetect Multi-Release JAR and include the manifest entry automatically.

To create a Multi-Release JAR right now is necessary to add the configuration by adding to the manifest the entry: Multi-Release: true

        <plugin>
          <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-jar-plugin</artifactId>
          <version>3.3.0</version>
          <configuration>
            <archive>
              <manifestEntries>
                <Multi-Release>true</Multi-Release>
              </manifestEntries>
            </archive>
          </configuration>
        </plugin>

This is pure boilerplate and unneeded since we can detect if a JAR is multi-release by simply checking if it contains the META-INF/versions/ directory.

My proposal is to detect the included files and check if a path contains that directory and automatically add the manifest entry.

This can be controlled with a property that by default will be enabled, and to restore the previous behavior it can be disabled:

    @Parameter( property = "maven.jar.detectMultiReleaseJar", defaultValue = "true" )
    private boolean detectMultiReleaseJar;

This will allow us to follow convention-over-configuration to not require to manually set the manifest entry for a JAR that we already know should contain the manifest entry.

Issue Links

• links to: GitHub Pull Request #57