code: protected Object evaluateDefaultValue()
              throws JspException
      {
          Object val = _defaultValue;
  
          List defaults = null;
          if (val instanceof String) {
              defaults = new ArrayList();
              defaults.add(val);
          }
          else {
              Iterator optionsIterator = null;
              optionsIterator = IteratorFactory.createIterator(val);
  
              // default value is optional so only warn
              if (optionsIterator == null && _defaultValue != null)
                  logger.warn(Bundle.getString("Tags_IteratorError",
                          new Object[]{getTagName(), "defaultValue", _defaultValue}));
  
              if (optionsIterator == null)
                  optionsIterator = IteratorFactory.EMPTY_ITERATOR;
  
              defaults = new ArrayList();
              while (optionsIterator.hasNext()) {
                  Object o = optionsIterator.next();
                  defaults.add(o.toString());
              }
          }
  
          return defaults;
      }
docs: Evaluate the defaultValues