code: protected String getStringImpl() throws SQLException {
  
          try {
              return StringConverter.inputStreamToString(getBinaryStreamImpl(),
                      "US-ASCII");
          } catch (IOException ex) {
              throw Exceptions.transformFailed(ex);
          }
      }
docs: Retrieves a string representing the XML value designated by this
  SQLXML instance. <p>
  
  @return a string containing the XML data.
  @throws SQLException if there is an error processing the XML value.