"AWT-EventQue-0" java.lang.NullPointerException is kicking my butt

[Selig Amsel]

So, I am making a rudimentary Minesweeper knockoff for a homework assignment. I am trying to call some of the methods in my Minesweeper class from my MineButton class. However, I get a NullPointerException. There are about a thousand questions about this particular issue, but I can't find a solution to my problem from those. Apparently something is null, but I've initialized everything properly (obviously not, though). I really need some help on figuring this out. The two classes that matter are shown below along with the stack trace.

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

public class MineButton extends JButton
{
	private int x;
	private int y;
	private Minesweeper play;
	
	public MineButton(Minesweeper play)
	{
		play = new Minesweeper();
		this.play = play;
	}
	
	public MineButton(int x, int y)
	{
		this.x = x;
		this.y = y;
		
		addMouseListener(new MouseHandler());
	}
	
	public void paintComponent(Graphics g)
	{
		super.paintComponent(g);
	}
	
	public void evaluateLClick(int x, int y)
	{	
		System.out.println(play.isMine(y, x));
	}
	
	private class MouseHandler extends MouseAdapter
	{
		final JToggleButton toggle = new JToggleButton();
		public void mouseClicked(MouseEvent e)
		{
			if (SwingUtilities.isLeftMouseButton(e))
			{
				if (toggle.isEnabled())
				{
					evaluateLClick(x, y);
					System.out.println("Left click on " + x + ", " + y);
				}
				repaint();
			}
			
			if (SwingUtilities.isRightMouseButton(e))// && e.getClickCount() == 1)
			{
				if (toggle.isEnabled())
				{
					System.out.println("Right click on " + x + ", " + y);
				}
				repaint();
			}
		}
	}
}

public class Minesweeper
{	
	private int[][] mineField;
	
	public Minesweeper()
	{
	}
	
	public Minesweeper(int[][] mineField)
	{
		this.mineField = mineField;
	}
	
	public int mineTotal()
	{
		int total = 0;
		
		for (int r = 0; r < mineField.length; r++)
		{
			for (int c = 0; c < mineField[r].length; c++)
			{
				if (mineField[r][c] == 1)
					total++;
			}
		}
		return total;
	}
	
	public int mineCount(int y, int x)
	{
		int count = 0;
		
		if (x == 0 && y == 0)
		{
			if (mineField[y][x+1] == 1) count++;
			if (mineField[y+1][x+1] == 1) count++;
			if (mineField[y+1][x] == 1) count++;
			return count;
		}
		else if (x == mineField.length-1 && y == 0)
		{
			if (mineField[y][x-1] == 1) count++;
			if (mineField[y+1][x-1] == 1) count++;
			if (mineField[y+1][x] == 1) count++;
			return count;
		}
		else if (x == 0 && y == mineField.length-1)
		{
			if (mineField[y-1][x] == 1) count++;
			if (mineField[y-1][x+1] == 1) count++;
			if (mineField[y][x+1] == 1) count++;
			return count;
		}
		else if (x == mineField.length-1 && y == mineField.length-1)
		{
			if (mineField[y-1][x] == 1) count++;
			if (mineField[y-1][x-1] == 1) count++;
			if (mineField[y][x-1] == 1)count++;
			return count;
		}
		else if (x == 0)
		{
			if (mineField[y-1][x] == 1) count++;
			if (mineField[y-1][x+1] == 1) count++;
			if (mineField[y][x+1] == 1) count++;
			if (mineField[y+1][x+1] == 1) count++;
			if (mineField[y+1][x] == 1) count++;
			return count;
		}
		else if (x == mineField.length-1) // fix
		{
			if (mineField[y-1][x] == 1) count++;
			if (mineField[y-1][x-1] == 1) count++;
			if (mineField[y][x-1] == 1) count++;
			if (mineField[y+1][x-1] == 1) count++;
			if (mineField[y+1][x] == 1) count++;
			return count;
		}
		else if (y == 0)
		{
			if (mineField[y][x-1] == 1) count++;
			if (mineField[y+1][x-1] == 1) count++;
			if (mineField[y+1][x] == 1) count++;
			if (mineField[y+1][x+1] == 1) count++;
			if (mineField[y][x+1] == 1) count++;
			return count;
		}
		else if (y == mineField.length-1)
		{
			if (mineField[y][x-1] == 1) count++;
			if (mineField[y-1][x-1] == 1) count++;
			if (mineField[y-1][x] == 1) count++;
			if (mineField[y-1][x+1] == 1) count++;
			if (mineField[y][x+1] == 1) count ++;
			return count;
		}
		else
		{
			if (mineField[y+1][x+1] == 1)// && mineField[x+1][y+1] == 0 || mineField[x=1][y+1] == 1)
				count++;
			if (mineField[y][x+1] == 1)// && mineField[x][y+1] == 0 || mineField[x][y+1] == 1)
				count++;
			if (mineField[y+1][x-1] == 1)// && mineField[x+1][y-1] == 0 || mineField[x+1][y-1] == 1)
				count++;
			if (mineField[y][x-1] == 1)// && mineField[x][y-1] == 0 || mineField[x][y-1] == 1)
				count++;
			if (mineField[y-1][x-1] == 1)// && mineField[x-1][y-1] == 0 || mineField[x-1][y-1] == 1)
				count++;
			if (mineField[y-1][x] == 1)// && mineField[x-1][y] == 0 || mineField[x-1][y] == 1)
				count++;
			if (mineField[y-1][x+1] == 1)// && mineField[x-1][y+1] == 0 || mineField[x-1][y+1] == 1)
				count++;
			if (mineField[y+1][x] == 1)// && mineField[x][y+1] == 0 || mineField[x][y+1] == 1)
				count++;
			return count;
		}
	}
	
	public boolean isMine(int x, int y)
	{
		if (mineField[x][y] == 1)
			return true;
		else 
			return false;
	}
	
	public void flagMine(int x, int y)
	{
		if (isMine(x, y))
			mineField[x][y] = 0;
	}
	
	public static void main(String[] args)
	{
		
		int[][] practiceMineField = { {0,0,0,0,0,0,1,0,0} ,
									  {0,0,0,0,0,0,0,0,1} ,
									  {0,0,0,0,1,0,0,0,0} ,
									  {0,1,0,0,1,0,0,0,0} ,
									  {0,0,0,1,0,0,0,0,0} ,
									  {0,0,1,0,0,0,0,0,0} ,
									  {0,0,0,0,0,0,0,0,0} ,
									  {0,0,0,0,0,0,0,1,0} ,
									  {1,0,0,0,0,1,0,0,0} };
						
		Minesweeper gameBoard = new Minesweeper(practiceMineField);
		
		// Tests
		//System.out.println(gameBoard.mineTotal());
		//System.out.println(gameBoard.mineCount(6, 6));
		//System.out.println(gameBoard.isMine(3, 3));
		
		new MineFrame();
	}
}

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at MineButton.evaluateLClick(MineButton.java:34)
at MineButton$MouseHandler.mouseClicked(MineButton.java:46)
at java.awt.AWTEventMulticaster.mouseClicked(AWTEventMulticaster.java:270)
at java.awt.Component.processMouseEvent(Component.java:6528)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
at java.awt.Component.processEvent(Component.java:6290)
at java.awt.Container.processEvent(Container.java:2234)
at java.awt.Component.dispatchEventImpl(Component.java:4881)
at java.awt.Container.dispatchEventImpl(Container.java:2292)
at java.awt.Component.dispatchEvent(Component.java:4703)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4898)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4542)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4462)
at java.awt.Container.dispatchEventImpl(Container.java:2278)
at java.awt.Window.dispatchEventImpl(Window.java:2739)
at java.awt.Component.dispatchEvent(Component.java:4703)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:746)
at java.awt.EventQueue.access$400(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:697)
at java.awt.EventQueue$3.run(EventQueue.java:691)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.
java:75)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.
java:86)
at java.awt.EventQueue$4.run(EventQueue.java:719)
at java.awt.EventQueue$4.run(EventQueue.java:717)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.
java:75)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:716)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.ja
va:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:
116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.ja
va:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

The error is on line 34 of my MineButton class and has something to do with play, but I don't know how to fix it.
Thanks for any help in advance.

[Campbell Ritchie]

Welcome to the Ranch

Please go through the stack trace again. Line 34 is empty, so it can't be there that you are suffering the Exception.

[Omar Rashwan]

In the MineButton class constructor you initialized the Minesweeper --- play -- in the Args to so this will call the non-arg constructor in
Minesweeper class --- which did not initialize the it the Array you guess ---
after that you assigned the new object to the MineButton instance variable play...
Look at this code

    public MineButton(Minesweeper play)
    {
        play = new Minesweeper();
        this.play = play;
    }

replace it with this code

    public MineButton(Minesweeper play)
    {
        //play = new Minesweeper();// that was the problem you re-initialized the play arg not the variable instance
        this.play = play;
    }