This example differs from Diffing a working copy against a repository example only in the the right-hand parameter passed to an SVNDiffClient: 

   1             /*
   2              * This corresponds to 'svn diff -rBASE'.
   3              */
   4             diffClient.doDiff(wcRoot, SVNRevision.UNDEFINED, SVNRevision.WORKING, SVNRevision.BASE,
   5                     SVNDepth.INFINITY, true, System.out, null);