My First Java program :-)

[308holes]

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;

class FindPrimes extends JFrame implements Runnable, ActionListener {
			Thread go;
			JLabel howManyLabel = new JLabel("Quantity: ");
			JTextField howMany = new JTextField("400",10);
			JButton display = new JButton("Display primes");
			JTextArea primes = new JTextArea(8,40);
			
			FindPrimes() {
					super("Find Prime Numbers");
					setSize(400, 300);
					setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
					Container content = getContentPane();
					BorderLayout bord = new BorderLayout();
					content.setLayout(bord);
					display.addActionListener(this);
					JPanel topPanel = new JPanel();
					topPanel.add(howManyLabel);
					topPanel.add(howMany);
					topPanel.add(display);
					content.add(topPanel, BorderLayout.NORTH);
					primes.setLineWrap(true);
					JScrollPane textPane = new JScrollPane(primes);
					content.add(textPane, BorderLayout.CENTER);
					setVisible(true);
			}
			
			public void actionPerformed(ActionEvent evt) {
				  display.setEnabled(false);
					if (go ==null) {
						 	go = new Thread(this);
							go.start();
					}
			}

			public void run() {
					int quantity = Integer.parseInt(howMany.getText());
					int numPrimes = 0;
					//candidate: the number the number the might be prime
					int candidate = 2;
					primes.append("First " + quantity + " primes:");
					while (numPrimes < quantity) {
							if (isPrime(candidate)){
								  primes.append(candidate + " " );
									numPrimes++;
							}
							candidate++;
					}
			}
			
			public static boolean isPrime(int checkNumber) {
					double root = Math.sqrt(checkNumber);
					for (int i = 2; i <= root; i++) {
							 if (checkNumber % i ==0)
							 		 return false;
					}
					return true;
		 }
		 
		 public static void main(String[] arguments) {
		 		FindPrimes fp = new FindPrimes();
		 }
 }