code: @Override
      public void setContentHandler(ContentHandler handler) {
          if (handler == null) {
              handler = base;
          }
          contentHandler = handler;
      }
docs: <b>SAX2</b>: Assigns the object used to report the logical content of an
  XML document. If a document handler was set, this content handler will
  supplant it (but XML 1.0 style name reporting may remain enabled).