Classes in the game

Question

am getting really frustrated because im trying to finish my assignment and ive hit a total brick wall, im sure the information is in my head i just can;t implement it.
am trying to write a simple game with a GUI which generates random number of pieces then the user takes a number of pieces the computer takes a number of pieces and so on until the last player takes the last piece and they lose.
Have done the GUI mainly, save for a couple of features I may add in if time. What im stuck on is the classes and inheritance. I want a class called Player which then extends to Enemy(computer) and Person. I don't know if the way Ive started means I can't do this or what
this is my code (again)
The main class:
import javax.swing.*;
import java.awt.event.*;
import java.util.Random;
public class Game extends JFrame
    public static void main (String [] args)
    new Game();
    Random generator = new Random();
   public int runningTotal = 10+generator.nextInt(100);
    String number = Integer.toString(runningTotal);
private Player human;
private Player enemy;
private JTextField text1;
private JButton button1;   
private JButton button2;
private JTextField text2;   
private JTextField text3;   
private JButton button3;
private JTextField text4;
private JTextField text5;
public JTextField text6;
private JTextField text7;
public Game()
    human = new Player();
    enemy = new Enemy();
    this.setSize(400,400);
    this.setTitle("Nim");
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     panel aPanel = new panel();
    JLabel label2 = new JLabel("Enter your name,then press OK");
    text2 = new JTextField(10);
    aPanel.add(label2);
    aPanel.add(text2);
    this.add(aPanel);
    this.add(aPanel);
    ClickListener c1 = new ClickListener();
    button1 = new JButton("OK");
    button1.addActionListener(c1);
    aPanel.add(button1);
    this.add(aPanel);
    JLabel label3 = new JLabel("Current Player");
    text3 = new JTextField(10);
    text3.setEditable(false);
    aPanel.add(label3);
    aPanel.add(text3);
    this.add(aPanel);
    this.add(aPanel);
    JLabel label4 = new JLabel("Enter your pick,then press My Turn");
    text4 = new JTextField(5);
    aPanel.add(label4);
    aPanel.add(text4);
    text4.setText(""+0+"");
    this.add(aPanel);
    this.add(aPanel);
    ClickListener c3 = new ClickListener();
    button3 = new JButton("My Turn");
    button3.addActionListener(c3);
    aPanel.add(button3);
    this.add(aPanel);
    JLabel label5 = new JLabel("Your last pick was");
    text5 = new JTextField(5);
    text5.setEditable(false);
    aPanel.add(label5);
    aPanel.add(text5);
    this.add(aPanel);
    this.add(aPanel);
    JLabel label6 = new JLabel("Winner");
    text6 = new JTextField(10);
    text6.setEditable(false);
    aPanel.add(label6);
    aPanel.add(text6);
    this.add(aPanel);
    this.add(aPanel);
    text7 = new JTextField(20);
    text7.setEditable(false);
    aPanel.add(text7);
    this.add(aPanel);
    ClickListener c2 = new ClickListener();
    button2 = new JButton("EXIT");
    button2.addActionListener(c2);
    aPanel.add(button2);
    this.add(aPanel);
    this.setVisible(true);
class panel extends JPanel
   public panel()
    JLabel label1 = new JLabel("Number of Pieces");
    text1 = new JTextField(20);
    text1.setText(number);
    this.add(label1);
    this.add(text1);
private class ClickListener
        implements ActionListener
    private int clickCount = 0;
    public void actionPerformed (ActionEvent e)
      String name = text2.getText();
      if (e.getSource() == button1)
            text3.setText(""+name+"");
       int pick = Integer.parseInt(text4.getText());
     int number = Integer.parseInt(text1.getText());
       runningTotal = (number - pick);
      if (pick < 10)
      if (e.getSource() == button3)
       text5.setText(""+pick+"");
       text1.setText(""+runningTotal+"");
      if (pick <= 0)
          text5.setText("Pick a number");
    if (runningTotal <=0)
          text7.setText("Game Over "+name+"");
         // human.checkWin();
      if (e.getSource()== button2)
         System.exit(0);
      text2.requestFocus();
[ /code]
The player class so far: import javax.swing.*;
public class Player
int runningTotal;
int win;
public JTextField text6;
public void checkWin()
if (runningTotal <= 0)
text6.setText("u win") ;
enemy so far has nothing in it, i need it to work out the number of pieces its taking from a formula.
Just a bit of advice from someone who knows what they are doing would help

Answer 1

If I understand your question, You cannot extend from two classes in Java. You cannot extend Player from Enemy and Person directly.
You can achieve this by using interfaces. Please read java tutorial from sun for more info.