Why is the array's content all the same. Copying doesn't help me either - Java

I'm a coding-beginner and have got a problem with my code. I'm working at an algorithm to create a kind of chessboard. But my array always gets overritten. I've read a lot of articels, but nothing has helped me.

My idea:

int pointsY [y] <--- y equals the row  
int pointsX [x] <--- x equals the column

After initializing the array, the content of should change to: current value + a random Integer.

public class draw extends JLabel {
private static final long serialVersionUID = 1L;

static int x;
static int y;
static int columns = 10;
static int rows = 10;
static int offset = 50;
static int size;
static int squareSizX;
static int squareSizY;
static int [] pointsX = new int[columns + 1];
static int [] pointsY = new int[rows + 1];
static Random r = new Random();

public static void draw() {

    Random r = new Random();
    squareSizX = cmain.frame.getWidth() / columns;
    squareSizY = cmain.frame.getHeight() / rows;

    for (int iy = 0; iy < pointsY.length; iy++) {
            pointsY[iy] = iy * squareSizY;
        }
    for (int ix = 0; ix < pointsX.length; ix++) {
        pointsX[ix] = ix * squareSizX;
    }
}

protected void paintComponent(Graphics g) {

    super.paintComponent(g);

    Graphics2D g2d = (Graphics2D) g;

    g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

    for (int iy = 0; iy < pointsY.length; iy++) {
        for (int ix = 0; ix < pointsX.length; ix++) {

            g.drawString("°", pointsX[ix], pointsY[iy]);

            if (iy < pointsY.length - 1) {
                g.drawLine(pointsX[ix], pointsY[iy], pointsX[ix], pointsY[iy + 1]);
            }

            if (ix < pointsX.length - 1) {
                g.drawLine(pointsX[ix], pointsY[iy], pointsX[ix + 1], pointsY[iy]);
            }

        }
    }

    repaint();
}

public static void randomize() {
    Random r = new Random();
    for (int ix = 0; ix < pointsX.length; ix++) {
        pointsX[ix] = pointsX[ix] + r.nextInt(offset);

    }

    for (int iy = 0; iy < pointsY.length; iy++) {

        pointsY[iy] = pointsY[iy] + r.nextInt(offset);

    }

}

}

When I run this code, they're all in one line, but I want that they are randomly distributed. I'm looking forward to your reply.