如何在java中创建不可变类？举例说明

    public final class immutablepoint {
        private final int x;
        private final int y;

        public immutablepoint(int x, int y) {
            this.x = x;
            this.y = y;
        }

        public int getx() {
            return x;
        }

        public int gety() {
            return y;
        }

        // example of returning a new instance instead of modifying the current one
        public immutablepoint move(int deltax, int deltay) {
            return new immutablepoint(this.x + deltax, this.y + deltay);
        }
    }

    public class Main {
        public static void main(String[] args) {
            ImmutablePoint point1 = new ImmutablePoint(1, 2);
            System.out.println("Point1: (" + point1.getX() + ", " + point1.getY() + ")");

            // Moving the point creates a new instance
            ImmutablePoint point2 = point1.move(3, 4);
            System.out.println("Point2: (" + point2.getX() + ", " + point2.getY() + ")");
            System.out.println("Point1 remains unchanged: (" + point1.getX() + ", " + point1.getY() + ")");
        }
    }