I've just released a new version of the JBuilder plugin for PMD. This release features enhancements to the copy/paste detector - the progress feedback should be more helpful, and the report is now displayed to provide more information about what files were affected.
Below is a screenshot of the copy/paste detector in action inside JBuilder:
I hope folks find this duplicate code detecting to be an interesting feature; it can drege up some interesting things, especially on large codebases.
And be sure to get the owner's manual - PMD Applied!