code: private String getIndex() {
  
          try {
              return parseMandatoryStringValue(XML_ELEMENT_INDEX);
          } catch (final Exception e) {
              LOG.info(Messages.get().getBundle().key(Messages.LOG_NO_INDEX_SPECIFIED_0), e);
              return null;
          }
      }
docs: Returns the configured Solr index, or <code>null</code> if the core is not specified.
  @return The configured Solr index, or <code>null</code> if the core is not specified.