This extension is one of the most popular extensions that people install in BlueJ.

We recently released BlueJ 5.0.0 which includes a breaking modification to the extensions API, so your existing extension will not run in BlueJ 5. As you may know, BlueJ 1-3 used Swing for its GUI and thus the extension API was based around Swing. BlueJ 4 had an awkward hybrid of Swing and JavaFX (which already caused problems with some extensions). BlueJ 5 has now fully transitioned to JavaFX and removed support for the old extensions API in favour of a very similar one based on JavaFX.

We have made a guide on how to convert extensions to BlueJ 5 here: https://bluej.org/extensions/writingextensions2.html#BJ5 The quick summary is that you need to update some package names, change any Swing GUI to the JavaFX equivalent and recompile against BlueJ 5. The effort involved will thus be proportionate to how much Swing GUI code you have in your extension.

If you have any questions about converting your extension, please let us know.

Problem: When attempting to set the location through the extension preference window of PMD for BlueJ 5.x or launching the extension from a context menu, a file not found exception occurs.

Cause: As the title notes, the main PMD distribution changed the entry-point script name for Linux/Mac from <pmd distro>/bin/run.sh or variations to just <pmd distro>/bin/pmd a while back (at least PMD v6.55 which is current in Homebrew, but also applies to the latest snapshot 7.x from the main website).

Reference:

These three spots were the only obvious references I found on cursory look.

Resolution: As a workaround, it works for my needs (in the extension by adding a symbolic link in the bin folder of the distribution (ln -s pmd run.sh.

For a more permanent resolution, switching to the current entry-point script name in code would probably be the forward-thinking way to handle it, and warn if using an older PMD distribution where the older expected entry point is present, but continue to execute the underlying, older PMD distribution.

On line 20 of "PMDExecExt.java" the method call "bluej.getCurrentFrame()" returns a null. BlueJ updated their source code, version 4.0.0 changed this methods return. This method now returns a null and this prevents PMD from working in BlueJ.

I've installed the PMD plugin and configured it (configuration options show in the preferences). My PMD is working or at least it is running, but in BlueJ I don't see the PMD option in the class context menu.