/**
 * Cell information for the Map.
 */

public class CellId
{
    public static final char ENTRANCE = '@';
    public static final char OPEN_PASSAGE = '.';
    public static final char STONE_WALL = '#';
    
    public static final char FIRST_KEY = 'a';
    public static final char FIRST_DOOR = 'A';
    
    private CellId ()
    {
    }
}
@@ -231,81 +231,35 @@
 nal 
-char FIRST_KEY = 'a';%0A    public static final char FIRST_DOOR = 'A';%0A    
+int DOOR_CODE = 32; // a-A%0A
 %0A   

Update CellId.java