How to make circles randomize in a JFrame when I r

public class SplatPanel extends JPanel
{
private Circle circle1, circle2, circle3, circle4, circle5;
private Rectangle rec1, rec2, rec3;

//  Constructor: Creates five Circle objects.

public SplatPanel()
{
  circle1 = new Circle (30, Color.red, 70, 35);
  circle2 = new Circle (50, Color.green, 30, 20);
  circle3 = new Circle (100, Color.cyan, 60, 85);
  circle4 = new Circle (45, Color.yellow, 200, 100);
  circle5 = new Circle (60, Color.blue, 350, 200);

  // (positionX, positionY, color, width, length)

  rec1 = new Rectangle (200, 40, Color.GRAY, 90, 70);
  rec2 = new Rectangle (150, 250, Color.red, 10, 10);
  rec3 = new Rectangle (40, 200, Color.pink, 50, 300);

  setPreferredSize (new Dimension(500, 400));
  setBackground (Color.black);
  }


//  Draws this panel by requesting that each circle draw itself.

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

  circle1.draw(page);
  circle2.draw(page);
  circle3.draw(page);
  circle4.draw(page);
  circle5.draw(page);
  rec1.draw(page);
  rec2.draw(page);
  rec3.draw(page);
 }

The objective is to make the circles randomize, how would I go about to randomize the circles so when I run the "Splat" program the circles will randomize in different places and sizes? I have a Rectangle class, a Circle class, a Splat class and then the SplatPanel class. I'm only assuming I would be using the randomizer in the the SplatPanel class

The problem is you are using hard coded values for the Circles. Instead you can randomize the values using the Random class

Random random = new Random();
int randX = random.nextInt(500);  // or whatever the width of your panel is
int randY = random.nextInt(400);  // or whatever the height of your panel is
int randRadius = random.nextInt(100); // max radius
Circle circle = new Circle(randRadius, Color.BLUE, randX, randY);

You could also use a List<Circle> to add the circles to and just loop through them in the paintComponent method (which is pretty common).

Here's a full running example

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;

public class SplatPanel extends JPanel {

    private static final int D_W = 500;
    private static final int D_H = 500;

    private List<Color> colors;
    private List<Circle> circles;
    Random random = new Random();

    public SplatPanel() {
        colors = createColorList();
        circles = new ArrayList<>();

        Timer timer = new Timer(100, new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                int randX = random.nextInt(D_W);  // or whatever the width of your panel is
                int randY = random.nextInt(D_H);  // or whatever the height of your panel is
                int randRadius = random.nextInt(100); // max radius
                Color color = colors.get(random.nextInt(colors.size()));
                Circle circle = new Circle(randRadius, color, randX, randY);
                circles.add(circle);
                repaint();
            }
        });
        timer.start();
    }

    private List<Color> createColorList() {
        List<Color> list = new ArrayList<>();
        list.add(Color.BLUE);
        list.add(Color.CYAN);
        list.add(Color.PINK);
        list.add(Color.ORANGE);
        list.add(Color.GREEN);
        list.add(Color.MAGENTA);
        list.add(Color.YELLOW);
        list.add(Color.RED);
        return list;
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        for (Circle circle : circles) {
            circle.drawCircle(g);
        }
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(D_W, D_H);
    }

    public class Circle {

        int radius, x, y;
        Color color;

        public Circle(int radius, Color color, int x, int y) {
            this.radius = radius;
            this.color = color;
            this.x = x;
            this.y = y;
        }

        public void drawCircle(Graphics g) {
            g.setColor(color);
            g.fillOval(x, y, radius * 2, radius * 2);
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                JFrame frame = new JFrame();
                frame.add(new SplatPanel());
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }
}