The Maven central repository does not have certain Sun Java jar files due to license restrictions. The work around is to download the files ourselves and put into the local Maven repository.  

            http://maven.apache.org/reference/standard-sun-jar-names.html

This directory contains the jar files should be copied to the corresponding directory under your local Maven repository.  This needs to be done everytime a "m2 clean" command is executed. After the copying, execute "m2 compile" command in the project directory (for example, \treebase-core directory) to verify the build is successful.