To build the SpotBugs plugin for Eclipse, you'll need to create the file eclipsePlugin/local.properties, containing a property eclipseRoot.dir that points to an Eclipse installation's root directory (see .github/workflows/release.yml for an example), then run the build.To prepare Eclipse environment only, run ./gradlew eclipse. See also detailed steps.
Although modules using the standard maven-compiler-plugin treated compiler warnings as errors, modules using the groovy-eclipse-compiler did not. Now all modules treat most compiler warnings as errors that must be resolved.