IntelliJ Idea mapstruct java: Internal error in the mapping processor: java.lang.NullPointerException
The solution is to update MapStruct to 1.4.1.Final or later version, see this issue for more details. You can also add -Djps.track.ap.dependencies=false at File | Settings (Preferences on macOS) | Build, Execution, Deployment | Compiler | Build process VM options as a workaround.