maven-source-plugin

                    <plugin>
                        <groupId>org.apache.maven.plugins</groupId>
                        <artifactId>maven-source-plugin</artifactId>
                        <version>${maven-source-plugin.version}</version>
                        <executions>
                            <execution>
                                <phase>package</phase>
                                <goals>
                                    <goal>jar-no-fork</goal>
                                </goals>
                            </execution>
                        </executions>
                    </plugin>

3.0.1