code: private IndexReader getIndexReader()
      {
          // removed flushInternal() call while reading
          if (reader == null)
          {
              try
              {
                  if (!isInitialized)
                  {
                      Directory sourceDir = FSDirectory.open(getIndexDirectory().toPath());
                      copy(sourceDir, index);
                      isInitialized = true;
                  }
                  reader = DirectoryReader.open(index);
              }
              catch (IndexNotFoundException infex)
              {
                  log.warn("No index found in given directory, caused by:", infex.getMessage());
              }
              catch (Exception e)
              {
                  log.error("Error while instantiating LuceneIndexer, Caused by :.", e);
                  throw new LuceneIndexingException(e);
              }
          }
          return reader;
      }
docs: Returns default index reader.
  
  @return index reader.