Draw a point: use a drawLine() method : Line « 2D Graphics « Java Tutorial

1. Java Tutorial
2. 2D Graphics
3. Line

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.util.Random;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class Points extends JPanel {

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

    Graphics2D g2d = (Graphics2D) g;

    g2d.setColor(Color.red);

    for (int i = 0; i <= 100000; i++) {
      Dimension size = getSize();
      int w = size.width ;
      int h = size.height;

      Random r = new Random();
      int x = Math.abs(r.nextInt()) % w;
      int y = Math.abs(r.nextInt()) % h;
      g2d.drawLine(x, y, x, y);
    }
  }

  public static void main(String[] args) {
    Points points = new Points();
    JFrame frame = new JFrame("Points");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.add(points);
    frame.setSize(250, 200);
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
  }
}

16.12.Line
	16.12.1.	Draw a line
	16.12.2.	draw Line from (10, 15) to (100, 115)
	16.12.3.	Line2D.Float
	16.12.4.	Draw a point: use a drawLine() method
	16.12.5.	A line is drawn using two points
	16.12.6.	Dash style line
	16.12.7.	Line dashes style 2
	16.12.8.	Lines Dashes style 3
	16.12.9.	Line Dash Style 4
	16.12.10.	Draw Dashed
	16.12.11.	Compares two lines are returns true if they are equal or both null.
	16.12.12.	Creates a region surrounding a line segment by 'widening' the line segment.