Thread: Recursive Maze Help

I am making a recursive maze that has to find the path. I have got it pretty well set up but I got the following errors when I ran it.
Any Help is greatly appreciated!

Maze Solver

1. Maze 1
2. Maze 2
3. Maze 3
4. Random Maze

Enter Number: 1

############
#...#......#
..#.#.####.#
###.#....#.#
#....###.#..
####.#.#.#.#
#..#.#.#.#.#
##.#.#.#.#.#
#........#.#
######.###.#
#......#...#
############Exception in thread "main" java.lang.NullPointerException
at MazeSolver.<init>(MazeSolver.java:24)
at MazeDriver.main(MazeDriver.java:106)

public class MazeDriver {
 
	public static void main(String args[])	
	{
		int input; //Number of maze
		Maze m = null;
		Scanner scanner = new Scanner(System.in);
 
		char[][] m1 = {{'#','#','#','#','#','#','#','#','#','#','#','#'},
                {'#','.','.','.','#','.','.','.','.','.','.','#'},
                {'.','.','#','.','#','.','#','#','#','#','.','#'},
                {'#','#','#','.','#','.','.','.','.','#','.','#'},
                {'#','.','.','.','.','#','#','#','.','#','.','.'},
                {'#','#','#','#','.','#','.','#','.','#','.','#'},
                {'#','.','.','#','.','#','.','#','.','#','.','#'},
                {'#','#','.','#','.','#','.','#','.','#','.','#'},
                {'#','.','.','.','.','.','.','.','.','#','.','#'},
                {'#','#','#','#','#','#','.','#','#','#','.','#'},
                {'#','.','.','.','.','.','.','#','.','.','.','#'},
                {'#','#','#','#','#','#','#','#','#','#','#','#'}};
 
 
		char[][] m2 = {{'#','#','#','#','#','#','#','#','#','#','#','#'},
                {'#','.','.','.','#','.','.','.','#','#','.','.'},
                {'#','.','#','.','.','.','#','.','.','.','.','#'},
                {'#','.','#','#','#','#','.','#','.','#','.','#'},
                {'#','.','.','.','#','#','.','.','.','.','.','#'},
                {'#','#','#','.','#','#','#','#','.','#','.','#'},
                {'.','.','.','.','.','.','.','.','.','.','#','#'},
                {'#','#','#','#','#','#','#','#','#','#','#','#'}};
 
		char[][] m3 = {{'#','#','#','#','#','#','#','#','#'},
                {'#','.','#','.','#','.','.','.','#'},
                {'#','.','.','.','#','.','#','#','#'},
                {'#','#','#','.','#','.','#','.','.'},
                {'.','.','.','.','.','.','#','.','#'},
                {'#','#','.','#','.','#','#','.','#'},
                {'#','.','.','#','.','#','.','.','#'},
                {'#','#','.','#','.','#','.','.','#'},
                {'#','#','#','#','#','#','#','#','#'}};
 
 
			do
			{
 
				System.out.println("Maze Solver");
				System.out.println("\n1. Maze 1");
				System.out.println("2. Maze 2");
				System.out.println("3. Maze 3");
				System.out.println("4. Random Maze");
 
 
				System.out.print("\nEnter Number: ");
				input = scanner.nextInt();
				if(input < 1 || input > 4)
				{
					System.out.println("Invalid Number!");
				}
			}while(input < 1 || input > 4);
 
 
			switch(input)
			{
 
				case 1:
					m = new Maze(m1, 2, 4);
				break;
 
				case 2:
					m = new Maze(m2, 6, 1);
				break;
 
				case 3:
					m = new Maze(m3, 4 , 3);
 
				break;
 
				case 4:
					m = new Maze();
				break;
 
			}	
 
			System.out.print(m.toString());
			MazeSolver ms = new MazeSolver(m, m.start, m.finish);
			ms.solve(0, ms.s);
 
 
 
 
	}
}

public class MazeSolver {
	int s;
	int f;
	Maze solveMaze;
	int x;
	int y;
	int size = solveMaze.Maze[0].length;
    boolean solved;
    boolean wall = false;
    int count=0;
 
 // Method Name		: MazeSolver
 	// Parameters		: Maze m, int start, int finish
 	// Partners     	: None
 	// Description		: Initializes Variables 
	public MazeSolver(Maze m, int start, int finish)
    {
    	s=start;
    	f=finish;
    	solveMaze = m;
    }
 
	 // Method Name		: Solve
 	// Parameters		: int x, int y
 	// Partners     	: None
 	// Description		: Solves the maze.
	public void solve(int x, int y) 
	{
        if (x==size && y==f) 
        {
            solved = true;
        }
        solveMaze.Maze[x][y] = 'x';
 
        if (solveMaze.Maze[x + 1][y] == '.') 
        {
            solve(x + 1, y);
            count++;
        }
        else if (solveMaze.Maze[x][y + 1] == '.') 
        {
            solve(x, y + 1);
            count++;
        }
        else if (solveMaze.Maze[x - 1][y] == '.') 
        {
            solve(x -1, y);
            count++;
        }
        else if (solveMaze.Maze[x][y-1] == '.') 
        {
            solve(x, y - 1);
            count++;
        }
        else 
        {
            wall = true;
        }
        if (wall) 
        {
            wall = false;
            solve(x, y);
        }
        if (solved)
        {
        	System.out.print("solved");
        	solveMaze.Maze.toString();
        }
 
 
 
 
 
 
	}
 
}

public class Maze {
 
	char Maze[][];
	public int start;
	public int finish;
	public int width;
	public int width2;
 
 
	 // Method Name		: Maze
	// Parameters		: char n, int s, int f
	// Partners     	: None
	// Description		: Initializes preset maze
 
	public Maze(char[][] m, int s, int f)
	{
		Maze= m;
		start=s;
		finish=f;
	}
public String toString()
	{
	    String output="";
	    for (int i=0; i<Maze.length; i++)
	    {
	    	for (int j =0; j<Maze[i].length; j++)
	    	{
	    		if(j==0)
	    		{
	    			output += "\n";
 
	    		}
	    		output += Maze[i][j];
	    	}
	    }
		return output;
	}
 
}

Exception in thread "main" java.lang.NullPointerException
at MazeSolver.<init>(MazeSolver.java:24)

Look at line 24 in MazeSolver and see what variable has a null value. Then backtrack in the code to see why that variable does not have a non-null value. If you can't tell which variable is null, add a println in front of line 24 that prints out the values of all the variables on line 24