Maven does not downloads a source and javadoc jar files by default.
This option should be added to its settings file in ~/.m2/settings.xml file like this:
<profiles>
<profile>
<id>downloadSources</id>
<properties>
<downloadSources>true</downloadSources>
<downloadJavadocs>true</downloadJavadocs>
</properties>
</profile>
</profiles>
<activeProfiles>
<activeProfile>downloadSources</activeProfile>
</activeProfiles>
Here is the link about this topic:
http://stackoverflow.com/questions/5780758/maven-always-download-sources-and-javadocs