code: private static void sigKill(String pid, boolean isProcessGroup,
                          long sleeptimeBeforeSigkill, boolean inBackground) {
  
      if(inBackground) { // use a separate thread for killing
        SigKillThread sigKillThread = new SigKillThread(pid, isProcessGroup,
                                                        sleeptimeBeforeSigkill);
        sigKillThread.setDaemon(true);
        sigKillThread.start();
      }
      else {
        sigKillInCurrentThread(pid, isProcessGroup, sleeptimeBeforeSigkill);
      }
    }
docs: Kills the process(OR process group) by sending the signal SIGKILL
  @param pid Process id(OR process group id) of to-be-deleted-process
  @param isProcessGroup Is pid a process group id of to-be-deleted-processes
  @param sleeptimeBeforeSigkill The time to wait before sending SIGKILL
  after sending SIGTERM
  @param inBackground Process is to be killed in the back ground with
  a separate thread