Viewing version source for multi release JAR (MRJAR)

Question

I'm trying to attach the Java 9 or Java 11 source for some projects released as MRJARs, namely jersey-container-jetty-http-3.0.2 and junit-platform-commons-1.4.0.

Looking at the jersey-container-jetty-http-3.0.2-sources.jar file in my ~/.m2/repository there is no META-INF/versions directory and the .java files in standard package locations are for Java 8 (pre module system). This is also the case if I unpack https://repo1.maven.org/maven2/org/glassfish/jersey/containers/jersey-container-jetty-http/3.0.2/jersey-container-jetty-http-3.0.2-sources.jar

This is a big bummer for my debugger :(

I was able to download the full source code from https://github.com/eclipse-ee4j/jersey/releases/tag/3.0.2, and it contains the following directories, with source:

containers/jetty-http/src/main/java11

containers/jetty-http/src/main/java8

I thought maybe this was just a Jersey problem, but looking at junit-platform-commons-1.4.0 I see a similar issue. Neither my ~/.m2/repository nor https://repo1.maven.org/maven2/org/junit/platform/junit-platform-commons/1.4.0/junit-platform-commons-1.4.0-sources.jar contain code for any java 9+ version but the release JAR contains /META-INF/versions/9/org/junit/platform/commons/util/ModuleUtils.class.

So my question: Is including source for multiple Java versions supported by Maven? If so, where are the Java 9+ source files be located?

Answer 1

The maven-source-plugin:jar goal which:

[...] bundles all the sources into a jar archive.

doesn't mention MRJAR explicitely but it has the parameter:

Name	Description
<includes>	List of files to include. Specified as fileset patterns which are relative to the input directory whose contents is being packaged into the JAR.