Anyhow, it seemed nice to write a PMD extension for BlueJ, so I knocked one out. I announced it on the bluej-discuss list and it seems to have been downloaded a few times already. Right now it just runs the basic and unused code rulesets, but I'll add more options as I get more feedback.
The report looks quite clunky (screenshot, just a JOptionPane.showMessageDialog), but I didn't want to do too much work on it before hearing from the BueJ folks on how best PMD should be integrated.
Using PMD? Get the owner's manual, PMD Applied!