For the VS 2017 build, I also saw no .class files and no .jar. So those are definitely missing for this generator. And l also saw no difference when building vtkjava specifically.
Regarding the parallel build, I meant the visual studio option for accelerating the build with multiple cores. I’m not sure how it is set in the GUI, since I always do visual studio builds on the command line and use the “-m” option:
msbuild VTK.sln /m:4 /property:Configuration=Release
The reason I was curious is that, if the dependencies chain is incorrectly generated for Visual Studio, then during a parallel build it is possible that vtkWrapHierarchy might use an input file that is only partly generated by a previous step. But I didn’t see a crash when using “-m:4” for my Visual Studio build, and as you said, you saw it specifically for a Ninja build.
In any case, if you ever see the vtkWrapHierarchy crash occur in the future, please let me know.