This is not the way to do it. As you can see in this maven mirror listing, the commons/lang sources are already available in all maven repositories that mirror central, so there is no need to build them yourself (BTW: if you build the project, you are installing the compiled binaries, not the sources, so even a success wouldn't have helped you).
Here's how to do it (Assuming you use eclipse):
- If you use m2eclipse, just right-click the project and select
Maven -> Download Sources
- If you use the maven-eclipse-plugin see the page about adding sources to libs
If you don't use eclipse, I know there are similar plugins for NetBeans and IntelliJ Idea.