I draw my map from a txt file. Would I have to write to the text file to notice the changes I made? Right now it changes the number in the array but the tile texture doesn't change. Do I have to do more than just change the number in the array?

public class Tiles {

public Image[] tiles = new Image[5];

public int[][] map = new int[64][64];

private Image grass, dirt, fence, mound;

private SpriteSheet tileSheet;

public int tileWidth = 32;
public int tileHeight = 32;

Player player = new Player();

public void init() throws IOException, SlickException {
    tileSheet = new SpriteSheet("assets/tiles.png", tileWidth, tileHeight);

    grass = tileSheet.getSprite(0, 0);
    dirt = tileSheet.getSprite(7, 7);
    fence = tileSheet.getSprite(2, 0);
    mound = tileSheet.getSprite(2, 6);
    tiles[0] = grass;
    tiles[1] = dirt; 
    tiles[2] = fence;
    tiles[3] = mound;

    int x=0, y=0;
BufferedReader in = new BufferedReader(new FileReader("assets/map.dat"));
String line;
while ((line = in.readLine()) != null) {
        String[] values = line.split(",");
    for (String str : values) {
            int str_int = Integer.parseInt(str);
            map[x][y]=str_int;
            //System.out.print(map[x][y] + " ");
            y=y+1;
        }
//System.out.println("");
x=x+1;
    y = 0;
}
    in.close();
}

public void update(GameContainer gc) {

}

public void render(GameContainer gc) {
    for(int x = 0; x < map.length; x++) {
        for(int y = 0; y < map.length; y ++) {
            int textureIndex = map[y][x];
            Image texture = tiles[textureIndex];
            texture.draw(x*tileWidth,y*tileHeight);
        }
    }
}

Mouse picking

public void checkDistance(GameContainer gc) {
    Input input = gc.getInput();

    float mouseX = input.getMouseX();
    float mouseY = input.getMouseY();

    double mousetileX = Math.floor((double)mouseX/tiles.tileWidth);
    double mousetileY = Math.floor((double)mouseY/tiles.tileHeight);

    double playertileX = Math.floor(playerX/tiles.tileWidth);
    double playertileY = Math.floor(playerY/tiles.tileHeight);

    double lengthX = Math.abs((float)playertileX - mousetileX); 
    double lengthY = Math.abs((float)playertileY - mousetileY);
    double distance = Math.sqrt((lengthX*lengthX)+(lengthY*lengthY)); 

    if(input.isMousePressed(Input.MOUSE_LEFT_BUTTON) && distance < 4) {
        System.out.println("Clicked");  
        if(tiles.map[(int)mousetileX][(int)mousetileY] == 1) {
            tiles.map[(int)mousetileX][(int)mousetileY] = 0;
        }
    }  

    System.out.println(tiles.map[(int)mousetileX][(int)mousetileY]);
}