code: protected void releaseWriterAndReaders()
     {
        if (indexWriter != null)
        {
           try
           {
              indexWriter.close();
           }
           catch (IOException e)
           {
              log.warn("Exception closing index writer: " + e.toString());
           }
           indexWriter = null;
        }
        if (indexReader != null)
        {
           try
           {
              indexReader.close();
           }
           catch (IOException e)
           {
              log.warn("Exception closing index reader: " + e.toString());
           }
           indexReader = null;
        }
        if (readOnlyReader != null)
        {
           try
           {
              readOnlyReader.release();
           }
           catch (IOException e)
           {
              log.warn("Exception closing index reader: " + e.toString());
           }
           readOnlyReader = null;
        }
        if (sharedReader != null)
        {
           try
           {
              sharedReader.release();
           }
           catch (IOException e)
           {
              log.warn("Exception closing index reader: " + e.toString());
           }
           sharedReader = null;
        }
     }
docs: Releases all potentially held index writer and readers.