Today, I would like to explain the improvement for maven plugin - buildNumber, that I talked in my previous message - short revision id for Git SCM.
IMPORTANT : This feature is present in the maven-buildnumber-plugin 1.1 version.
 
You can specify the 
length for the Git revision.   To enable this feature you have to specify the new tag 
 
 <shortRevisionLength>
in the 
 <configuration>
section.  For exemple:
The associated maven output informs us about the detection of 
shortRevisionLength tag and print the length of the revision that will be used in buildNumber formatting:
Some implementation details 
This feature uses internally the 
git rev-pasre --short (see associated 
git help section) command and the revision length is set to minimum 4 characters.   So you can't have the revision id shorter then 4 characters. Even if you specify the length between 0 and 4, the plugin will inform you about this situation and the minimum value (4) will be used.
UPDATED: If your maven build can't find the dependency for maven-buildnumber-plugin 1.1 , try to force the dependency update  by adding option "-U" for your mvn command.