One of the key advantages of open source software besides being available free
of charge is – well – that its source is available to developers reusing existing
open source libraries.

Having the source available in your IDE when developing against an API is such
a great thing that I wonder why so few open source projects care to make this
asset easily available to their “customers”.

Maven and its central repository (aka ibiblio) provides a great facility to
publish sources along with the jars. All it takes is a small snippet added to
your project’s POM (or its parent POM) before you upload the bundle to the
repo:

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

I really wonder why this isn’t the default in Maven and encourage all open
source developers to provide sources for their releases.

Consuming the sources is handled by the IDE plugins Maven provides but again
this is not the default:

mvn -DdownloadSources=true idea:idea

or

mvn -DdownloadSources=true eclipse:eclipse

Et voilà: all sources attached to the jars and available through
Shift-Click or whatever your IDE’s shortcut is.