private void closeFile(){
  if (plogStream != null) {
    try {
      plogStream.close();
      logger.info("File " + plogFilename + " closed.");
    }
 catch (    IOException e) {
      logger.warn("Unable to close file cleanly: " + plogFilename);
    }
 finally {
      plogStream=null;
    }
  }
}

private void closeFile ( ) { if ( plogStream != null ) { try { plogStream . close ( ) ; logger . info ( "File " + plogFilename + " closed." ) ; } catch ( IOException e ) { logger . warn ( "Unable to close file cleanly: " + plogFilename ) ; } finally { plogStream = null ; } } }
close plog file . this operation is idempotent to allow convenient cleanup at thread exit .
