VTK 9 and Java- vtk.jar not automatically generated. Also location of wrapper dlls

That should be

cd $vtk_build_dir\Wrapping\Java
dir /s/B *.java >javafiles
javac -d ..\..\java @javafiles
cd ..\..\java
jar --create -f  ..\lib\java\vtk.jar vtk\*.class

then run

cd $vtk_build_dir\Wrapping\Java\vtk\sample
java -cp $vtk_build_dir\lib\java\vtk.jar Demo.java