Simple GUI - Help

Question

Hi, for my Java class, we have to write a simple GUI for a program that we wrote last week. This is what I have so far:
import javax.swing.*;
import java.awt.*;
import java.util.Random;
/* Class Kozyra which contains main method */
public class Kozyra {     
    /* Method question: gets the user to enter whether or not he/she wants to continue
     * running the program */
    public static String question(){
          String s, answer;
          boolean valid;
          do{
               s = JOptionPane.showInputDialog("Continue? (Y/N or P to Pause)");
             answer = s.toUpperCase();
             valid = answer.equals("Y") || answer.equals("N") || answer.equals("P");
             if(!valid){
                    JOptionPane.showMessageDialog(null, answer + " is not a valid response. Please retype.");
             } // end if
             if(answer.equals("P")){
                  JOptionPane.showMessageDialog(null, "Game Paused.  Press OK to continue.");
          }while (!valid); // end do-while
          return answer;
    } // end method question
    public static void frame(){
         Homework3GUI frame = new Homework3GUI();
          frame.setTitle("CRAPS");
          frame.setLocationRelativeTo(null);
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          frame.setSize(600,400);
          frame.setLayout(new FlowLayout(FlowLayout.LEFT, 10, 20));
          frame.setVisible(true);
    } // end method frame
    /* Main method: creates new object called player and determines whether or not the game
     * continues running*/
    public static void main(String[] args){     
        frame();
        String answer = "Y";
          Dice player = new Dice(100, "");
          JOptionPane.showMessageDialog(null,"Welcome to CRAPS, " + player.getName());
          while(!player.busted() && !player.reachedGoal() && answer.equals("Y")){           
            player.begin();
            if(!player.busted() && !player.reachedGoal()){
                    answer = question();
               } // end if
               else{
                    answer = "N";
               } // end if
          } // end while                 
    } // end main
} // end class Homework3
/* Beginning of class Dice (driver) */
class Dice extends JPanel{
     // Declare variables
     private int amount, betValue;
     private int roll = 0;
    private String name;
        private boolean win, lose;
        private JTextField text1, text2, text3, text4, text5, text6;
     /* Constructor */
    public Dice(int amount, String name){
        this.name = name; // this refers to instance variabls
        this.amount = amount;
    } // end method Dice
    public void layout(){
         setLayout(new FlowLayout(FlowLayout.LEFT, 10, 20));
         text1 = new JTextField();
         text2 = new JTextField();
         text3 = new JTextField();
         text4 = new JTextField();
         text5 = new JTextField();
         text6 = new JTextField();
         add(text1, null);
         add(text2, null);
         add(text3, null);
         add(text4, null);
         add(text5, null);
         add(text6, null);
         text1.setSize(15,25);
         text2.setSize(15,25);
         text3.setSize(15,25);
         text4.setSize(15,25);
         text5.setSize(15,25);
         text6.setSize(15,25);
         text1.setLocation(10,10);
         text2.setLocation(10,40);
         text3.setLocation(10,70);
         text4.setLocation(10,100);
         text5.setLocation(10,130);
         text6.setLocation(10,160);
         setVisible(true);
    } // end method layout
    /* Prompts the user to enter his/her name using the scanner class and returns it as a string */
    public String getName(){
         String name = JOptionPane.showInputDialog("Please enter your name: ");
        return name;
    } // end method getName
    /* Asks the user to input his/her bet and determines if it is valid */
     private void getBet(){
          String betValueString = JOptionPane.showInputDialog("You have $" + amount +
               ".  Please enter your bet: $");
          betValue = Integer.parseInt(betValueString);
          if(betValue > amount){
                  betValueString = JOptionPane.showInputDialog("You only have $" + amount +
                       ".  Please enter a bet that is less than or equal to $" + amount + ":  $");
                  betValue = Integer.parseInt(betValueString);
          } // end if
          if(betValue < 1){
               betValueString = JOptionPane.showInputDialog("You have $" + amount +
                    ".  Please enter an amount greater than $1:  $");
                  betValue = Integer.parseInt(betValueString);
          } // end if
     } // end getBet
     /* Simulates the craps game and returns win */
     private boolean playGame(){
           int answer = roll();
           text1.setText("Your roll is: " + answer);
           win = answer == 11 || answer == 7;
           lose = answer == 2 || answer == 12;
           if(!(win || lose)){
                int point = answer;
                text2.setText("Your point value is: "+ point);
                while(!(win||lose)){
                     answer = roll();
                     text3.setText("Your total is: " + answer);
                     win = answer == point;
                     lose = answer == 7;
                } // end while
           } // end if
           return win;
      } // end method game
     /* Simulates the rolling of the die */
     public int roll(){
           int die1 = (int)(6*Math.random() + 1);
           int die2 = (int)(6*Math.random() + 1);
           text4.setText("You rolled " + die1 + " and " + die2 + ".  ");
           return die1 + die2;
      } // end method roll
     /* Informs the user of the result of his/her game and updates the amount of "money" */
     private void displayMessage(boolean win){
          if(win == true){
               text5.setText("Congratulations, you won that round.  You bet $" + betValue +
                    " so you won $" + betValue + ". You now have $" + (amount += betValue));
          } // end if
          else{
               text5.setText("Sorry, you lost that round.  You bet $" + betValue +
                    " so you lost $" + betValue + ".  You now have $" + (amount -= betValue));
          } // end else if
     } // end method displayMessage
    /* Determines if the user has busted or won and will or will not continue playing */
    public boolean terminate(){
         boolean go;
         if(busted() == true){
              text6.setText("Sorry, you have lost. :( Somewhere, the world's tiniest violin is " +
                   "playing you a sad song.");
              go = false;
         } // end if
         else if(reachedGoal() == true){
              text6.setText("CONGRATULATIONS!  YOU HAVE BEAT THE ODDS AND WON!" +
                   " THE COSMOS SALUTES YOU! GO SPEND YOUR WINNINGS");
              go = false;
         } // end else if
         else
              go = true;
         return go;
    } // end method terminate
    /* Determines of goal of amount greater than or equal to $300 has been reached */
    public boolean reachedGoal(){
         return amount >= 300;
    } // end method reachedGoal
    /* Determines if the user has run out of money to play with */
    public boolean busted(){
        return amount <= 0;
    } // end method busted
    /* Calls other methods in order to play game */
    public void begin(){
        getBet();
        playGame();
        displayMessage(win);
        terminate();
    } // end begin
} // end DiceI'm sure it's simple and terrible and all but I really don't know what I'm doing, and this is my first time writing a GUI (plus my professor's teaching consisted of him telling us to go look online). Firstly I can't get anything to show up on the frame. Secondly, it compiles but does not run and I am getting the following two errors:
Exception in thread "main" java.lang.NullPointerException
at Dice.roll(Kozyra.java:182)
at Dice.playGame(Kozyra.java:155)
at Dice.begin(Kozyra.java:238)
at Kozyra.main(Kozyra.java:56)
Note: C:\Program Files\Xinox Software\JCreatorV4LE\MyProjects\Honors2\Kozyra.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Any help would be appreciated, as I am becoming increasingly frustrated (I can't find where the pointer exception is and I have no idea what the "note" one is...). Thanks.

Answer 1

Thanks, Corlett.
The Homework3GUI thing was a vestige from something else that I missed correcting. However, I still cannot get anything to show up on the JFrame...Also, what does private static final long serialVersionUID = 54645635L; do?
This is how the code reads now:
import javax.swing.*;
import java.awt.*;
import java.util.Random;
public class Kozyra2 extends JFrame{
      // returns true if user wishes to continue playing
     public static boolean playAgain() {
          return JOptionPane.YES_OPTION == JOptionPane.showConfirmDialog(null,
               "Play again ?", "Do you wish to continue playing?", JOptionPane.YES_NO_OPTION);
      } // end method playAgain
      // builds and shows a GUI.
     public static void buildAndShowGUI(){
          Kozyra2 frame = new Kozyra2();
             frame.setTitle("CRAPS");
             frame.setLocationRelativeTo(null);
             frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
             frame.setSize(600,400);
            frame.setLayout(new FlowLayout(FlowLayout.LEFT, 10, 20));
             frame.setVisible(true);
      } // end buildAndShowGUI
     // Main method: gets this show on the road.
     public static void main(String[] args){
            buildAndShowGUI();
            Player player = new Player(100, enterName());
          JOptionPane.showMessageDialog(null,"Welcome to CRAPS, " + player.getName());
          while(player.play() && playAgain());
     } // end main method
     // returns the name entered by the user
     private static String enterName() {
          return JOptionPane.showInputDialog("Please enter your name: ");
     } // end method enterName
} // end class
class Player extends JPanel{
     private static final long serialVersionUID = 54645635L;
     private static final int TARGET_BALANCE = 300;
     private int balance;
     private String name;
     private JTextField[] text = null;
     public Player(int stake, String name){
          this.name = name;
             this.balance = stake;
             this.layoutPanel();
     } // end constructor
     public String getName() {
          return this.name;
     } // end method getName
     private void layoutPanel() {
            setLayout(new FlowLayout(FlowLayout.LEFT, 10, 20));
             text = new JTextField[6];
             for (int i=0; i<6; i++) {
               text[i] = newTextField(10+i*30);
               add(text, null);
          } // end for loop
          setVisible(true);
     } // end method layoutPanel
     private JTextField newTextField(int y) {
          JTextField t = new JTextField();
          t.setSize(15,25);
          setLocation(10,y);
          return t;
     } // end method newTextField
     // returns the users bet balance
     private int getBet(){
          while (true) {
               try {
                    String response = JOptionPane.showInputDialog("You have " + balance + ". Your bet ? ");
                    int bet = Integer.parseInt(response);
                    if(bet>=1 && bet<=balance)
                         return bet;
                    JOptionPane.showMessageDialog(null, "Oops: An integer between 1 and " + balance + " is required.");
          } catch (NumberFormatException E) {
               JOptionPane.showMessageDialog(null, "Oops: An integer value is required.");
          } // end try-catch
          } // end while loop
     } // end method getBet
     // returns true of the user wins this round.
     private boolean playRound(int bet){
          int score = roll();
          text[1].setText("Your score is: " + score);
          boolean win = (score == 11 || score == 7);
          boolean lose = (score == 2 || score == 12);
          int previousScore = score;
          while ( !(win||lose) ) {
               score = roll();
               text[3].setText("Your score is: " + score);
          win = (score == previousScore);
          lose = (score == 7);
          previousScore = score;
          } // end while loop
          if (win) {
               balance += bet;
               text[5].setText("You won. You won $" + bet + ". You now have $" + balance);
          } // end if statement
          else {
               balance -= bet;
               text[5].setText("You lost. You now have $" + balance);
          } // end else
          return win;
     } // end method playRoung
     // returns the total of rolling a pair of dice.
     public int roll(){
          int die1 = (int)(6*Math.random() + 1);
          int die2 = (int)(6*Math.random() + 1);
          int total = die1 + die2;
          text[4].setText("You rolled " + die1 + " and " + die2 + " = " + total);
          return total;
     } // end method roll
// are we there yet?
     public boolean checkBalance(){
          if (balance <= 0) {
               text[6].setText("Busted!");
          return true;
          } // end if statement
          if (balance >= TARGET_BALANCE) {
               text[6].setText("Congratulations! Go spend your winnings.");
               return true;
          } // end if statement
          return false;
     } // end method checkBalance
     public boolean play(){
          int bet = getBet();
          playRound(bet);
          return checkBalance();
     } // end method play
} // end class Player