Files Tested
When you invoke PMD, it is run on the current file.

Rules
The "unused code" and "basic" rulesets are run on the code you select - these rulesets catch things like unused local variables, empty try blocks,
unused imports, empty catch blocks, and so forth.

You can view all the PMD rules with examples and details at
http://pmd.sf.net/.

Future Plans
Continue to respond to the Gel community's feedback