Using interfaces or not.

'''Option 1:''' Using interfaces
 * + Implementation is separated from its implementation
 * - duplicates number of files
 * - more work


'''Option 2:''' Not using interfaces
 * + less files 
 * + you ain't gonna need it
 * - Spring wants one approach or the other (<tx:annotation-driven  proxy-target-class="true" />). 

Chosen option 2.