I do not understand why I keep getting this error for the output

Question

So below we have the code from the first of my two files, titled Game (keep scrolling down to see the second file + the issue)

public class Game
{
    private static final int PLAYING=0;
    private static final int RED_WINS=1;  
        private static final int BLACK_WINS=2;
        private static final int DRAW=3;
            private static final int RED=4;
            private static final int BLACK=5;
            private static final int EMPTY=6;
        private static final int WALL=7;
    private static int board[][];

public Game()
{


    int board[][]={{WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL},
                {WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL},
                {WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL},
                {WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL},
                {WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL},
                {WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL,EMPTY,WALL}};


}
public  void draw()
{
    for(int r= 0; r< board.length; r++)
        {

            for(int c= 0; c<board[0].length; c++)
                {
                    if(board[r][c]==WALL)
                    {
                        char Wall='|';
                        board[r][c]=Wall;
                    }
                        if(board[r][c]==EMPTY)
                    {
                        char Empty=' ';
                        board[r][c]=Empty;
                    }
                    if(board[r][c]==BLACK)
                    {
                        char Black='B';
                        board[r][c]=BLACK;
                    }
                    if(board[r][c]==RED)
                    {
                        char Red='R';
                        board[r][c]=RED;
                    }
                    System.out.print(board[r][c] + "");
                }
                System.out.print("\n");
       }
}
}

And Below is the code from the second file, MainFile

import java.util.Scanner;
public class MainFile
{
    public static void main(String[]args)
    {
        Game a=new Game();
        a.draw();
    }
}

When I press compile, the output says Process completed and everything seems fine at first, but when I press run file I get the following runtimerror,could I know what I'm doing wrong and how can I fix it?

Exception in thread "main" java.lang.NullPointerException
    at Game.draw(Game.java:28)
    at MainFile.main(MainFile.java:7)