Update on tileMap Class
posY += 32;
        }
        posX += 32;


You have your tile sizes hardcoded in the TileMap ... in an obscure place (render code).

Consider placing them as constants in Tile or TileMap. That way, upscaling to 64x64 tiles is a lot easier.

public static BufferedImage getTileImage(int texKey1)
{
    BufferedImage image;
    switch(texKey1)
    {
        case 1:
        {
            image = Grass.texture;
            break;
        }
        case 2:
        {
            image = Dirt.texture;
            break;
        }
        case 3:
        {
            image = Tree.texture;
            break;
        }

        case 36:
        {
            image = Blank.texture;
            break;
        }
        default:
        {
            image = Blank.texture;
            break;
        }
    }
    return image;
}


You could use a Map here. Map&lt;Integer, BufferedImage&gt;, or better, Map&lt;Integer,Tile&gt;. Then you just have to get the Tile from the map, and ask that for the image. And if it's null you can return a blank.