Need some help, pleeaaase!!

[popshopper]

I keep getting a null pointer exception from the paint method.
It seems that there is a null in the player.display, but I can't find it. any help would be great. Sorry, but the style seems not to have made the transition.
Thanks
B.

<font size=2.5>import java.awt.*;
import java.awt.event.*;
import java.applet.*;
public class Nim extends Applet
                 implements ActionListener {
   private NimBoard theBoard;
   private Button reset, row1, row2, row3, newseries;
   private TextField amountRemoved;
   private Label title1, title2;
   private int matches= 0;
   private boolean exceptionerror, numbererror;
public Player currentPlayer, otherPlayer; 
public boolean checkname; 
private Player player1, player2;  
   
  
   public void init() {
   
     theBoard = new NimBoard(12);
     Player player1 = new Player("Scarface");
     Player player2 = new Player("The Hustler");
   currentPlayer = player1;
  otherPlayer= player2;  
     
     reset= new Button("New Game");
     add(reset);
     reset.addActionListener(this);
     
     row1= new Button("Row 1");
     add(row1);
     row1.addActionListener(this);
     
     row2= new Button("Row 2");
     add(row2);
     row2.addActionListener(this);
     
     row3= new Button("Row 3");
     add(row3);
     row3.addActionListener(this);
     
     title1= new Label("Enter the amount of matchsticks you wish removed, and then select row:");
     add(title1);
     
     amountRemoved= new TextField (2);
     add(amountRemoved);
     amountRemoved.addActionListener(this); 
     
     newseries = new Button("New Series");
     add(newseries);
     newseries.addActionListener(this);
     
     
     
      repaint();
   } // end of init
   
private void playerSwitch(){

if (checkname){
      currentPlayer= player2;
   otherPlayer= player1;}
   else
   currentPlayer= player1;
otherPlayer= player2;
}
public boolean checkname (){
boolean current = false;
if (currentPlayer.getname().equals (player1.getname()))
current = true;
return current;
}
   public void actionPerformed (ActionEvent e) {       
   
   if (e.getSource()== reset)
   theBoard= new NimBoard(12);
  
if (e.getSource() == newseries) 
   repaint();

try {   
   
   if (e.getSource() == row1){
   matches= Integer.parseInt(amountRemoved.getText());
   if (theBoard.moveAllowed(1,matches))
   theBoard.play(1, matches);
else{
numbererror = true;}
  
}
   
   if (e.getSource() == row2){
   matches= Integer.parseInt(amountRemoved.getText());
   if (theBoard.moveAllowed(2, matches)){
theBoard.play(2, matches);}
else{ 
numbererror = true;}  
 
}
if (e.getSource() == row3){
   matches= Integer.parseInt(amountRemoved.getText());
   if (theBoard.moveAllowed(3, matches)){
   theBoard.play(3, matches);}
else{
   numbererror = true;}
  
}
   amountRemoved.setText("");
   } // end of try
   
   catch (NumberFormatException err) {
   exceptionerror = true;}
   
 if (theBoard.gameOver()){
  repaint();
amountRemoved.setText("");}
  
amountRemoved.setText("");
repaint();
   } // end of actionPerformed

   public void paint( Graphics g ) {
      
      //if (Play
      //g.drawString("It is The Hustler's turn next", 50, 400);
      //else
      //g.drawString("It is Scarface's turn next", 50, 400);
      
      if (theBoard.gameOver()){
      g.drawString("Game Over!!! Player "+ currentPlayer.getname()+" has won!!!", 50, 100);
      ;}
      else
      theBoard.display(g);
      player1.display(g);
      
      
      if((exceptionerror) | | (numbererror)){
      g.drawString("Illegal Move", 50, 300);
      exceptionerror = false;
      numbererror = false;}
      else
      theBoard.display(g);
      
      
      
      
   } // end of paint
} // end of the applet class Nim

// The class NimBoard is to represent the state of a board at
// any time, and to provide methods for modifying a board and
// displaying a board.
 
class NimBoard {
 public boolean allowed, gameover = false;
   
   private int firstRow, secondRow, thirdRow;
      // private variables to hold the numbers
      // of matchsticks in the three rows
    
   public NimBoard(int rowLength) {  
     // constructor method, used to initialise a game board
     
     firstRow= rowLength;
     secondRow= rowLength;
     thirdRow= rowLength;
        
   } // end of constructor NimBoard
    
   public void play(int row, int matchsticks) {
      // method to "register" a move
      
      if  (row == 1){
      firstRow= firstRow-matchsticks;}
   
   if  (row == 2){
   secondRow= secondRow-matchsticks;}

if (row == 3){
thirdRow= thirdRow-matchsticks;}
      
      
          
   } // end of play
   
 public boolean moveAllowed(int row, int matchsticks) {
  allowed= true;  
   
   if (firstRow+secondRow+thirdRow <2) {
   allowed = false;}
  
if (matchsticks <= 0){
   allowed = false;}
    
if (row == 1){ 
   if  (matchsticks > firstRow)
   allowed = false;}

  if (row == 2){
   if (matchsticks > secondRow)
    allowed= false;}

if (row == 3){
if (matchsticks > thirdRow)    
    allowed= false;}

   
   return allowed; }  // end of moveAllowed
    
   public boolean gameOver() {
      // method to check whether the game is over
   if(firstRow +secondRow+ thirdRow<2) {
   gameover= true;}
return gameover;
   } // end of gameOver
    
   private void drawRow(Graphics g, int matchsticks, int y) {
      // method to draw one row of the game board (private!)
      // parameter y is for the y-coordinate of the row
      int x;
      int counter;
      counter= matchsticks;
     x= 50;  // sets initial x value for each row
      while (counter>0) {
      g.fillRect(x,y,5,30);
      x= x+10;
      counter= counter-1;
      }      
      
   } // end of drawRow
    
   public void display(Graphics g) {
      // method to display the three rows of the game board
      
      drawRow(g,firstRow, 100);
      drawRow(g,secondRow,150);
      drawRow(g,thirdRow, 200); 
      
        
   } // end of display
       
} // end of the class NimBoard
 class Player {
 
 private String name;
private int creditLeft = 5;
private int playercredit = 0;
 
 
public Player (String playerName){

String name = playerName;


}// end of player construction method

public String getname(){
return name;
}
public int getcredit(){
return creditLeft;
}
public int playercredit(){

playercredit = creditLeft;
return playercredit;
}

public boolean creditout(){
if (creditLeft == 0)
return true;
else
return false;
}

public void display(Graphics g){

g.drawString(name, 250, 400);
g.drawString("Credit's left: "+playercredit, 275, 400);
}


}

(code tags added by Marilyn for readability)
[This message has been edited by Marilyn deQueiroz (edited November 15, 2001).]

[Brian MacDonald]

Hi,
I've just realised that my username was incorrect
oops,
sorry.

[Paul Stevens]

Brian could you edit your post and put code tag around it.

[Brian MacDonald]

Sorry,
I am a complete beginner at this!!!
Also, I forgot to say. This is an assignment so I wouldn't like
help in the way of actual code. But of the life of me, I can't
see where I've went wrong. Any help any one could give me would be great, thanks
Sorry once again.

[Paul Stevens]

Look at player1, player2 and name. Look where you create instance variables and then where you use new. See anything wrong?

[Brian MacDonald]

I'm not sure, we've only started the course, and the commands I'm
using are the same as those in the book. Should I create instance
variables outside init? I'll continue to
muddle through. I'm getting the variable
coming up as null now, so is definitely just
a matter of the way I'm creating them. I've
been at this all day (I'm Scottish!!!) and
I've been stuck for a while now, I'm sure I'll get it.
thanks
[This message has been edited by Brian MacDonald (edited November 15, 2001).]

[Cindy Glass]

The problem is that you declared them outside of init - which is fine, but then you RE-declared them inside the init() method. This effectively gave you NEW variables local only to the init() method, which you then did stuff with.
When init() was over - poof! the local variables are gone and now all that is left are the original variables which were never initialized with any values .
If you just USE the variables - without redeclaring them (by naming the variable "type"), the code in init() will use the variabled declared outside.
Player player1 = . . . // declares a variable
player1 = . . . // uses a variable without redeclaring it
[This message has been edited by Cindy Glass (edited November 15, 2001).]

[Paul Stevens]

By the way Brian, very noble of you to only want a little help and not have someone else code it for you. In case you didn't get what Cindy pointed out.
In your Player class you define name as an instance variable.
Private String name;
Within your constructor you do:

public Player (String playerName){
String name = playerName;

}// end of player construction method

You created another variable called name used only within the constructor. So your name instance variable is null. That is why you get the error. The other methods attempted to use name (instance variable) which was still null.
Just say
name = playerName;
Same goes for player1 and player2. I know you just wanted hints but I think now you might understand what happened.

[Brian MacDonald]

oops!!
Thank you.