import vtk.vtkNativeLibrary;
import vtk.vtkMath;


public class DistanceBetweenPoints 
{
	// -----------------------------------------------------------------
	// Load VTK library and print which library was not properly loaded
	static 
	{
		if (!vtkNativeLibrary.LoadAllNativeLibraries()) 
		{
			for (vtkNativeLibrary lib : vtkNativeLibrary.values()) 
			{
				if (!lib.IsLoaded()) 
				{
					System.out.println(lib.GetLibraryName() + " not loaded");
				}
			}
		}
		vtkNativeLibrary.DisableOutputWindow(null);
	}
	// -----------------------------------------------------------------
	
	public static void main(String s[]) 
	{					  
		// Create two points.
		double p0[] = new double[] {0.0, 0.0, 0.0};
		double p1[] = new double[] {1.0, 1.0, 1.0};
		
		// Find the squared distance between the points.
		vtkMath squaredDistance = new vtkMath();
		double squaredDist = squaredDistance.Distance2BetweenPoints(p0, p1);
		
		// Take the square root to get the Euclidean distance between the points.
		double distance = Math.sqrt(squaredDist);
		
		// Output the results.
		System.out.println("Squared Distance:" + " " + squaredDist);
		System.out.println("Distance:" + " " + distance);

	}		  
}

import vtk.vtkNativeLibrary;
import vtk.vtkMath;


public class DistanceBetweenPoints 
{
	// -----------------------------------------------------------------
	// Load VTK library and print which library was not properly loaded
	static 
	{
		if (!vtkNativeLibrary.LoadAllNativeLibraries()) 
		{
			for (vtkNativeLibrary lib : vtkNativeLibrary.values()) 
			{
				if (!lib.IsLoaded()) 
				{
					System.out.println(lib.GetLibraryName() + " not loaded");
				}
			}
		}
		vtkNativeLibrary.DisableOutputWindow(null);
	}
	// -----------------------------------------------------------------
	
	public static void main(String s[]) 
	{					  
		// Create two points.
		double p0[] = new double[] {0.0, 0.0, 0.0};
		double p1[] = new double[] {1.0, 1.0, 1.0};
		
		// Find the squared distance between the points.
		vtkMath squaredDistance = new vtkMath();
		double squaredDist = squaredDistance.Distance2BetweenPoints(p0, p1);
		
		// Take the square root to get the Euclidean distance between the points.
		double distance = Math.sqrt(squaredDist);
		
		// Output the results.
		System.out.println("Squared Distance:" + " " + squaredDist);
		System.out.println("Distance:" + " " + distance);

	}
}

Update DistanceBetweenPoints.java