How do I create an uber source jar with Maven? - maven

Question

Is there a well-known way to create an uber source jar? In other words, a jar of all the source code for a project and all its dependencies (or at least those that have a -sources.jar)?
I've looked into doing it with the maven-assembly-plugin, but using a dependencySet with includes of *.*.*.sources.* (or *.sources) doesn't work because those are not actually dependencies of the project, and I don't want to add them all.

Answer 1

You can use the maven-shade-plugin to create an uber jar. Just include the following within your <build> tag -
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.0.0</version>
<executions>
<execution>
<id>source-jar</id>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<createSourcesJar>true</createSourcesJar>
<artifactSet>
<includes>
<include>...</include>
</includes>
</artifactSet>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
To modify the configuration, you can use Resource Transformers within org.apache.maven.plugins.shade.resource package.
And to define the contents of the jar, you can further use includes and excludes within the filters.

Answer 2

I found some information on working with sources in the maven-dependency-plugin.
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<executions>
<execution>
<id>src-dependencies</id>
<goals>
<goal>unpack-dependencies</goal>
</goals>
<phase>prepare-package</phase>
<configuration>
<classifier>sources</classifier>
<failOnMissingClassifierArtifact>false</failOnMissingClassifierArtifact>
<outputDirectory>${project.build.directory}/sources</outputDirectory>
<includeGroupIds>{your group prefix}</includeGroupIds>
<includes>**/*.java</includes>
<includeScope>runtime</includeScope>
</configuration>
</execution>
So if I do that, and then run a maven-assembly-plugin referencing the unpacked files, I can do it in two steps.
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<execution>
<id>uber-source</id>
<goals>
<goal>single</goal>
</goals>
<phase>package</phase>
<configuration>
<descriptors>
<descriptor>ubersource.xml</descriptor>
</descriptors>
<outputDirectory>${deploy.internal.directory}</outputDirectory>
<finalName>${project.artifactId}</finalName>
</configuration>
</execution>
</executions>
</plugin>
with a file set in the assembly descriptor ubsersource.xml:
<fileSet>
<directory>${project.build.directory}/sources</directory>
<outputDirectory>.</outputDirectory>
</fileSet>
And then I get my uber source jar...
There is perhaps a subtle distinction in the way the maven-assembly-plugin and maven-dependency-plugin treats sources. If you reference classifier sources in a dependencySet of an assembly descriptor, it looks for sources that are actual dependencies in your pom -- not that useful. However, in maven-dependency-plugin, referencing sources classifier means that sources of your dependencies. Hence why this solution works.
I also wrapped this up in my own plugin using mojo-executor to make it single step, and single declaration in my pom, but that's optional
This is a lot more pom code, but I like it better than the maven-shade-plugin because it does just what I want, and nothing more.