vtkPlanes not making planes

I’m attempting to make a vtkPlanes object with the following Java code:

vtkPlanes planes = new vtkPlanes();
planes.SetPoints(planePoints);
planes.SetNormals(planeNormals);

Where planePoints is a vtkPoints object and planeNormals is a vtkDataArray. When I call planes.GetNumberOfPlanes(), it always returns 0. What am I missing? Is there something I need to do to make it forms the planes? As usual the documentation is less than informative. Thanks for any information you can provide.

Not quite sure about the Java implementation of vtk, but typically in C++ I need to call a update function to make sure the output is as configured.
Does

planes.update();

exist, or work?

I think I figured it out - for some reason vtkDataArray is initializable when it really shouldn’t be - you have to use something like vtkDoubleArray or vtkFloatArray