code: public static CmsSolrSpellchecker getInstance(CoreContainer container) {
  
          if (null == instance) {
              synchronized (CmsSolrSpellchecker.class) {
                  if (null == instance) {
                      @SuppressWarnings("resource")
                      SolrCore spellcheckCore = container.getCore(CmsSolrSpellchecker.SPELLCHECKER_INDEX_CORE);
                      if (spellcheckCore == null) {
                          LOG.error(
                              Messages.get().getBundle().key(
                                  Messages.ERR_SPELLCHECK_CORE_NOT_AVAILABLE_1,
                                  CmsSolrSpellchecker.SPELLCHECKER_INDEX_CORE));
                          return null;
                      }
                      instance = new CmsSolrSpellchecker(container, spellcheckCore);
                  }
              }
          }
  
          return instance;
      }
docs: Return an instance of this class.
  
  @param container Solr CoreContainer container object in order to create a server object.
  
  @return instance of CmsSolrSpellchecker