Some case, you need to generate source code from your project which is maven 2 based.

Please have a look to maven-source plugin by adding a short code below into your pom.xml

<plugin>
	<groupId>org.apache.maven.plugins</groupId>
	<artifactId>maven-source-plugin</artifactId>
	<executions>
		<execution>
			<id>attach-sources</id>
			<goals>
				<goal>jar</goal>
			</goals>
		</execution>
	</executions>
</plugin>

By default it will generate jar named as: ${project.artifactId}-${project.version}-source.jar