Modify the LabeledPoint class of Exercise E15.15 so that it implements the Comparable interface. Sort points first by their x-coordinates. If two points have the same x-coordinate, sort them by their y-coordinates. If two points have the same x- and y-coordinates, sort them by their label. Write a tester program that checks all cases by inserting points into a TreeSet.

Data from Exercise E15.15

A labeled point has x- and y-coordinates and a string label. Provide a class LabeledPoint with a constructor LabeledPoint(int x, int y, String label) and hashCode and equals methods. Two labeled points are considered the same when they have the same location and label.