code: private Object getUnconfiguredAttributeValue(EvaluationContext context, ExtendedAttributeDefinition attributeDef) throws ConfigEvaluatorException {
  
          Object rawValue = null;
  
          // no value in config then try ibm:variable if set
  
          rawValue = variableEvaluator.lookupVariableExtension(context, attributeDef);
  
          // no value in config, no ibm:variable, try defaults
          if (rawValue == null) {
              String[] defaultValues = attributeDef.getDefaultValue();
              if (defaultValues != null) {
                  rawValue = Arrays.asList(defaultValues);
              }
          }
  
          return rawValue;
      }
docs: Try to determine a value from variable or defaults for the AD.
  
  @param attributeDef
  @param context
  @return
  @throws ConfigEvaluatorException