I am not sure of what you are asking, but we are using DFS inside our servlet, which runs in tomcat, to allow us to distribute files in a cleaner, easier, method then an NFS share.
To make things easier for us (especially operations) we have each of our servlets act as a datanode. This way each of our servers (web server), which only uses around 10GB of disk space, can take advantage of the rather cheap 40-100GB drives that are in them for the purpose of DFS.
