code: private String getValueWithDefault(String value, String manifestKey) {
          if (StringUtils.isEmpty(value) && manifest != null) {
              value = manifest.getMainAttributes().getValue(manifestKey);
          }
  
          return value;
      }
docs: Returns a value's default if the initial value is null or empty.
  
  @param value The initial value.
  @param manifestKey The manifest key from which to obtain the default value.
  @return The initial value or, if it was null or empty, the default value.