first of all, which OS are you testing on, and which VTK version are you using?
In VTK 9.0, vtkNativeLibrary.LoadAllNativeLibraries() returns a “boolean”, hence it cannot return a “null”.
Also, please check whether UnsatisfiedLinkError exceptions are thrown. If yes, please provide the exact stack trace, which will tell us a lot.
I don’t have much experience with Eclipse, but I would ensure that the “-Djava.library.path” system property is passed to the “java” command even when you run your project in “Release” mode.
Are you using a block of code like this?
for (vtkNativeLibrary lib : vtkNativeLibrary.values())
System.out.println(lib.GetLibraryName() + " not loaded");
What’s the output?