code: public void optimize() throws IOException {
  
          if ((m_index != null) && LOG.isInfoEnabled()) {
              LOG.info(
                  Messages.get().getBundle().key(
                      Messages.LOG_INDEX_WRITER_MSG_OPTIMIZE_2,
                      m_index.getName(),
                      m_index.getPath()));
          }
          int oldPriority = Thread.currentThread().getPriority();
          // we don't want the priority too low as the process should complete as fast as possible
          Thread.currentThread().setPriority(Thread.NORM_PRIORITY / 2);
          m_indexWriter.forceMerge(5);
          Thread.currentThread().setPriority(oldPriority);
      }
docs: @see org.opencms.search.I_CmsIndexWriter#optimize()
  
  As optimize is deprecated with Lucene 3.5, this implementation
  actually calls {@link IndexWriter#forceMerge(int)}.<p>