code: public WireFeed build(Reader reader) throws IllegalArgumentException, FeedException {
          final SAXBuilder saxBuilder = createSAXBuilder();
          try {
              if (xmlHealerOn) {
                  reader = new XmlFixerReader(reader);
              }
              final Document document = saxBuilder.build(reader);
              return this.build(document);
          } catch (final JDOMParseException ex) {
              throw new ParsingFeedException("Invalid XML: " + ex.getMessage(), ex);
          } catch (final IllegalArgumentException ex) {
              throw ex;
          } catch (final Exception ex) {
              throw new ParsingFeedException("Invalid XML", ex);
          }
      }
docs: Builds an WireFeed (RSS or Atom) from an Reader.
  <p>
  NOTE: This method delages to the 'AsbtractFeed WireFeedInput#build(org.jdom2.Document)'.
  <p>
  
  @param reader Reader to read to create the WireFeed.
  @return the WireFeed read from the Reader.
  @throws IllegalArgumentException thrown if feed type could not be understood by any of the
  underlying parsers.
  @throws FeedException if the feed could not be parsed