Trouble Creating a DFS Maze

Code :

---

import java.util.*;
 
public class MazeGenerator
{
public void init()
{
    String Maze[][] = new String [20][20];
 
    for (int i =0; i <20; i++) {
        for (int j = 0; j < 20; j++) {
            Maze[i][j] = "#";
        }
    }
 
    generate(Maze);
 
    for (int i =0; i <20; i++) {
        for (int j = 0; j < 20; j++) {
            System.out.print(" " + Maze[i][j]);
        }
        System.out.println("");
    }
}
 
public void generate (String Maze[][])
{
    Stack <String> CellStack = new Stack<String>();
    int TotalCells = Maze.length * Maze.length;
    int x = 10, y = 10;
 
    String CurrentCell = Maze[x][y];
    Maze[x][y] = "-";
    CellStack.push(CurrentCell);
    int VisitedCell = 1;
 
    boolean EastT, WestT, NorthT, SouthT;
 
    while(VisitedCell < TotalCells)
    {
        String EAST = Maze[x+1][y];
        String WEST = Maze[x-1][y];
        String NORTH = Maze[x][y+1];
        String SOUTH = Maze[x][y-1];
 
        if(EAST == "#")
            EastT = true;
        else
            EastT = false;
 
        if(WEST == "#")
            WestT = true;
        else
            WestT = false;
 
        if(NORTH == "#")
            NorthT = true;
        else
            NorthT = false;
 
        if(SOUTH == "#")
            SouthT = true;
        else
            SouthT = false;    
 
        if(WestT == true || EastT == true || NorthT == true || SouthT == true)
        {
            double Random = (int) (Math.random() * 4) + 1;
 
            switch ((int) Random)
            {   
                case 1: 
                if(EastT == true){   
                    Maze[x+1][y] = "-";
                    CurrentCell = EAST;
                    break;
                }
                else 
                    break;
 
                case 2:
                if(WestT == true){   
                    Maze[x-1][y] = "-";
                    CurrentCell = WEST;
                    break;
                }
                else
                    break;
 
                case 3:
                if(NorthT == true){   
                    Maze[x][y+1] = "-";
                    CurrentCell = NORTH;
                    break;
                }
                else
                    break;
 
                case 4:
                if(SouthT == true){   
                    Maze[x][y-1] = "-";
                    CurrentCell = SOUTH;
                    break;
                }
                else
                    break;
            }
            CurrentCell = "-";
            CellStack.push(CurrentCell);
            VisitedCell++;
        }
        else
        {
            CurrentCell = CellStack.pop();
        }
    }
}
}

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The Program is trying to create a maze out of a 2D Array, where "#" represents a wall and "-" represents an empty space. When I run the program, I get the error : EmptyStackException(), in the else part of the if statement. Whats the reason for this error? Any help would be very useful.