Eclipse plugin project "checkstyle internal error" says "cannot initialize module TreeWalker - Unable to instantiate '...ForbidCertainImportsCheck'"

2
votes

I haven't looked at my Eclipse plugin project for a few weeks, but after I updated to Neon.1, I noticed the following error in the Problems view:

Checkstyle execution failed due to an internal error. Please check the error log for details.

In the error log, I saw things like this:

!MESSAGE Checkstyle-Plugin: cannot initialize module TreeWalker - Unable to instantiate 'com.github.sevntu.checkstyle.checks.coding.ForbidCertainImportsCheck' class, it is also not possible to instantiate it as com.puppycrawl.tools.checkstyle.checks.annotation.com.github.sevntu.checkstyle.checks.coding.ForbidCertainImportsCheck, com.puppycrawl.tools.checkstyle.checks.blocks.com.github.sevntu.checkstyle.checks.coding.ForbidCertainImportsCheck, [deleted numerous similar class names], com.puppycrawl.tools.checkstyle.com.github.sevntu.checkstyle.checks.coding.ForbidCertainImportsCheckCheck. Please recheck that class name is specified as canonical name or read how to configure short name usage http://checkstyle.sourceforge.net/config.html#Packages. Please also recheck that provided ClassLoader to Checker is configured correctly.

After I saw this in my neon.1 workspace, I also noticed that my older workspace running in Mars.2 was also showing the same problem.

1
javaeclipseeclipse-plugincheckstyle

1 Answers

2
votes

I've managed to resolve this.

The parent POM of the project I work on had a change to its checkstyle configuration, and it now requires adding the "seventu" auxiliary checkstyle plugin, which I found at https://github.com/sevntu-checkstyle/sevntu.checkstyle . Once I installed that (and did the usual "Maven Update Projects" invocation), the errors went away.