exception in thread "main" java.lang.nullpointerexception (Knights Tour program)

Can anyone help me figure out where I'm wrong in this?
I keep getting the error "Exception in thread "main" java.lang.NullPointerException" and don't know how to fix it.

Code Java:

public class Brute
 {
	 public static void main(String[] args)
	 {   
		 int[][]chessBoard = new int[8][8];
		 init(chessBoard);  
 
		 chessBoard = traverse(chessBoard,0,0);  
		 print(chessBoard);      
	}  
 
	public static int [][] traverse(int[][] board, int ver, int hor)  
	{  
		if(boardTraversed(board))
		{  
			return board; 
		}  
 
		board[ver][hor] = 1;  
		if (ver > 1 && hor > 0 && board[ver-2][hor-1] == 0)  
		{  
			return traverse(board, ver-2, hor-1);  
		}  
		if(ver > 1 && hor < 7 && board[ver-2][hor+1] == 0)  
		{  
			return traverse(board,ver-2,hor+1);  
		}    
		return null;
	}  
 
	public static void init(int[][] array)
	{  
		for(int i = 0; i < array[0].length; i++)
		{  
			for(int a = 0; a < array.length; a++)
			{  
				array[i][a] = 0;  
			}  
		}  
	}  
 
	public static void print(int[][] array)
	{  
		for(int i = 0; i < array[0].length; i++)
		{  
			System.out.println();  
			for(int a = 0; a < array.length; a++)
			{  
				System.out.print(" " + array[i][a] + " ");  
			}  
		}  
	}     
 
	public static boolean boardTraversed(int board[][])
	{    
		for(int i = 0; i < board[0].length; i++)
			for(int a = 0; a < board.length; a++) 
				if(board[i][a] == 0)  
					return false;  
 
		return true;
	}
 }