java,android,system-properties,sources
as Hacketo linked to Where is android.os.SystemProperties android.os.SystemProperties is hidden, non public API, that can be seen at raw version http://grepcode.com/file_/repository.grepcode.com/java/ext/com.google.android/android/2.3_r1/android/os/SystemProperties.java/?v=source One of the ways to call it (though may be not available in some versions) is using reflection. So the code is ike String serial = null; if (Build.VERSION.SDK_INT...
java,maven,maven-plugin,sources
You can already do this with the maven source plugin. See https://maven.apache.org/plugins/maven-source-plugin/jar-mojo.html where there are includes and excludes parameters.