code: @Override
      public File getFileWithDefault(String key, String file) {
          String value = get(key);
          if (value == null) {
              return new File(baseDirectory, file);
          } else {
              return new File(baseDirectory, value);
          }
      }
docs: Get a File property or a default value when property cannot be found in
  any configuration file.
  The file object is constructed using <code>new File(basedir, value)</code>.
  
  @param key  the key
  @param file the default file
  @return the file object