There are no source jars in the maven repository, they are not being attached during the install. The source plugin is defined in the pluginManagement section of the parent pom resteasy-jaxrs-all, but not in the plugins section. Putting the following in the plugins section should attach the sources for all projects:

<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-source-plugin</artifactId>
</plugin>