This is Java Programing.There are already two options box and ball.

Add a shape of oval to the option of shape in the programing of BOXBALLOVAL.

import java.awt.*;

import java.awt.event.*;

import java.util.*;

import java.util.Timer;

import javax.swing.*;

public class BOXBALLOVAL {

public static void main(String[] args) {

new myframe();// creating main jframe instance

}

}

class myframe extends JFrame

{

Container c;

JPanel panel;

JButton addbutton, removebutton;

JLabel counter, ballsize;

JTextField size_input;

JComboBox cb;

buttonListener handle;

myDrawboard myboard;

JFrame mainFrame;

public myframe()

{

super("Your title");

c = getContentPane();

size_input = new JTextField(5);

counter = new JLabel("Count : ");

ballsize = new JLabel("Size : ");

size_input.setText("50");

addbutton = new JButton("Add");

removebutton = new JButton("Remove");

cb = new JComboBox();

cb.addItem("Ball");

cb.addItem("Box");

handle = new buttonListener();

addbutton.addActionListener(handle);

removebutton.addActionListener(handle);

panel = new JPanel();

panel.add(ballsize);

panel.add(size_input);

panel.add(addbutton);

panel.add(removebutton);

panel.add(counter);

panel.add(cb);

myboard = new myDrawboard();

c.add(myboard.panel, BorderLayout.CENTER);

c.add(panel, BorderLayout.SOUTH);

setSize(800, 600);

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

setVisible(true);

// update screen (refresh)

Timer timer = new Timer();

timer.schedule(new myTimer(), 0, 16);

}

class myTimer extends TimerTask

{

@Override

public void run() {

repaint();

}

}

class buttonListener implements ActionListener {

int i;

public void actionPerformed(ActionEvent action)

{

if (action.getSource() == addbutton) {

if (!size_input.getText().equals("")) {

try

{

myboard.additem(Integer.parseInt(size_input.getText()), cb.getSelectedItem().toString());

counter.setText(" Count : " + myboard.countItem()+ " ");

}

catch (NumberFormatException e)

{

System.out.println(e);

JOptionPane.showMessageDialog(null, "Enter only number!", "Invalid Input", JOptionPane.INFORMATION_MESSAGE);

}

}

else

{

JOptionPane.showMessageDialog(null, "Enter the Object size!", "Input needed", JOptionPane.INFORMATION_MESSAGE);

}

}

if (action.getSource() == removebutton)

{

myboard.removeBall();

counter.setText(" Count : " + myboard.countItem()+ " ");

}

}

}

}

class myDrawboard

{

private static int count = 0;

Graphics2D g2;

MyPanel panel = new MyPanel();

public void additem(int size, String shape)

{

count++;

panel.addShape(size, shape);

}

public String countItem() {

return Integer.toString(count);

}

public void removeBall() {

if (panel.deleteShape()) {

count--;

}

}

}

class MyPanel extends JPanel

{

ArrayList myArrayList = new ArrayList();

public MyPanel()

{

setBackground(Color.BLACK);

}

public void addShape(int size, String shape)

{

Random randomGenerator = new Random();

int x = randomGenerator.nextInt(200);

int y = randomGenerator.nextInt(200);

int R = randomGenerator.nextInt(256);

int G = randomGenerator.nextInt(256);

int B = randomGenerator.nextInt(256);

int vx = randomGenerator.nextInt(10)+2;

int vy = randomGenerator.nextInt(10)+2;

Color randomcolor = new Color(R, G, B);

if (shape == "Box")

{

Box box = new Box();

box.setInfo(size, x, y, randomcolor, vx, vy);

myArrayList.add(box);

}

else // shape==ball

{

Ball ball = new Ball();

ball.setInfo(size, x, y, randomcolor, vx, vy);

myArrayList.add(ball);

}

}

public boolean deleteShape()

{

if (myArrayList.size() > 0)

{

myArrayList.remove(myArrayList.size() - 1); // remove the last one

return true;

}

return false;

}

public void paintComponent(Graphics g)

{

Graphics2D g2 = (Graphics2D) g;

g2.setColor(Color.BLACK);

g2.fillRect(0,0,getWidth(), getHeight());

for (int i = 0; i < myArrayList.size(); i++)

{

myArrayList.get(i).update(getWidth(), getHeight());

myArrayList.get(i).drawObject(g2);

}

}

}

interface DrawObject

{

void drawObject(Graphics2D g2);

void update(int width, int height);

}

class Ball implements DrawObject

{

private int size;

int x;

int y;

int velX;

int velY;

private Color color;

public void setInfo(int size, int x, int y, Color randomcolor, int vx, int vy)

{

this.size = size;

this.x = x;

this.y = y;

this.velX = vx;

this.velY = vy;

this.color = randomcolor;

}

public void drawObject(Graphics2D g2)

{

g2.setColor(color);

g2.fillOval(x, y, size * 2, size * 2);

g2.setFont(new Font("SansSerif", Font.BOLD, 50));

// g2.drawString("cs211",x,y);

g2.drawString("CS",100,100);

}

//Ball moving

public void update(int width, int height)

{

x += velX;

if(x < 0 || x > width-size*2)

velX *= -1;

y += velY;

if(y < 0 || y > height-size*2)

velY *= -1;

}

}

class Box implements DrawObject

{

private int size;

int x;

int y;

int velX;

int velY;

private Color color;

private Rectangle square;

public void setInfo(int size, int x, int y, Color randomcolor, int vx, int vy)

{

square = new Rectangle(x, y, size, size);

this.velX = vx;

this.velY = vy;

color = randomcolor;

}

public void drawObject(Graphics2D g2)

{

g2.setColor(color);

g2.fillRect(square.x, square.y, square.width, square.height);

}

//box moving

public void update(int width, int height)

{

square.x += velX;

if(square.x < 0 || square.x > width-square.width)

velX *= -1;

square.y += velY;

if(square.y < 0 || square.y > height-square.height)

velY *= -1;

}

}