Untitled

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.util.ArrayList;

import javax.swing.JPanel;

public class LightningPanel extends JPanel {

    private static final long serialVersionUID = 1L;
    private ArrayList<Point> thePoints;

    public void setPoints(ArrayList<Point> points) {
        this.thePoints = points;
    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);

        Graphics2D g2d = (Graphics2D) g;

        g2d.setColor(Color.blue);
        g2d.setStroke(new BasicStroke(5));

        for (int i = 0; i < thePoints.size() - 1; i++) {
            int x1 = (int) thePoints.get(i).getX();
            int y1 = (int) thePoints.get(i).getY();
            int x2 = (int) thePoints.get(i+1).getX();
            int y2 = (int) thePoints.get(i+1).getY();
            g2d.drawLine(x1, y1, x2, y2);
        }
    }
}