### Question:
Plane { public Ray3d getIntersection(Plane plane) { if (MathUtil.isZero(1d - plane.getNormal().dot(myNormal))) { return null; } Vector3d rayDir = myNormal.cross(plane.getNormal()); Vector3d cross = rayDir.cross(myNormal); Ray3d crossLine = new Ray3d(myPoint, cross); return new Ray3d(plane.getIntersection(crossLine), rayDir); } Plane();  Plane(Vector3d point, Vector3d normal);  Plane(Vector3d pt1, Vector3d pt2, Vector3d pt3); static Vector3d unitProjection(Vector3d planeNormal, Vector3d vect); double getDistance(Vector3d position); Ray3d getIntersection(Plane plane); Vector3d getIntersection(Ray3d ray); Vector3d getIntersection(Vector3d ptA, Vector3d ptB); Vector3d getNormal(); Vector3d getPoint(); List<Vector3d> getSegmentIntersection(Vector3d ptA, Vector3d ptB); boolean hasIntersection(Vector3d ptA, Vector3d ptB); boolean isInFront(Vector3d position, double distance); boolean onSameSide(Vector3d ptA, Vector3d ptB); void setNormal(Vector3d normal); void setPoint(Vector3d point); @Override String toString(); Vector3d unitProjection(Vector3d vect);  }### Answer:
@Test public void testGetIntersectionWithRay() { Vector3d planePos = new Vector3d(-40.78934, -154.897456, 50.56); Vector3d planeNormal = new Vector3d(0., 0., -1.); Plane plane = new Plane(planePos, planeNormal); Vector3d rayPos = new Vector3d(20.987, 25.678, 5.); Vector3d rayDir = new Vector3d(0., 0., 1.); Ray3d ray = new Ray3d(rayPos, rayDir); Vector3d intersect = plane.getIntersection(ray); Vector3d expected = new Vector3d(20.987, 25.678, 50.56); assertEquals(intersect, expected); assertTrue(MathUtil.isZero(planeNormal.dot(intersect.subtract(planePos)))); }