public void killProcTree(int pid, int signal) {
      List<Integer> children = BY_PARENT.get(pid);
      if (children != null) {
        for (int child : children) {
          killProcTree(child, signal);
        }
      }
      if (LOG.isDebugEnabled()) {
        LOG.debug("Sending signal " + signal + " to PID " + pid);
      }
      sendSignal(pid, signal);
    }
public void killProcTree(int pid, int signal)