void Threads::add(JavaThread* p, bool force_daemon) {

  {- -------------------------------------------
  (1) (assert)
      ---------------------------------------- -}

      // The threads lock must be owned at this point
      assert_locked_or_safepoint(Threads_lock);

  {- -------------------------------------------
  (1) JavaThread::initialize_queues() を呼んで, 
      G1GC 用のキュー(SATB and dirty card queues)の初期化を行っておく.
      ---------------------------------------- -}

      // See the comment for this method in thread.hpp for its purpose and
      // why it is called here.
      p->initialize_queues();

  {- -------------------------------------------
  (1) Threads::_thread_list にこのスレッドを追加する.
      ---------------------------------------- -}

      p->set_next(_thread_list);
      _thread_list = p;

  {- -------------------------------------------
  (1) _number_of_threads フィールドの値を増やしておく.
      ---------------------------------------- -}

      _number_of_threads++;

  {- -------------------------------------------
  (1) (変数宣言など)
      ---------------------------------------- -}

      oop threadObj = p->threadObj();
      bool daemon = true;

  {- -------------------------------------------
  (1) daemon スレッドでない場合は, _number_of_non_daemon_threads フィールドの値を増やしておく.
      ---------------------------------------- -}

      // Bootstrapping problem: threadObj can be null for initial
      // JavaThread (or for threads attached via JNI)
      if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
        _number_of_non_daemon_threads++;
        daemon = false;
      }

  {- -------------------------------------------
  (1) (プロファイル情報の記録) (See: UsePerfData, ThreadService)
      ("java.threads.daemon", "java.threads.live", "java.threads.livePeak", "java.threads.started")
      ---------------------------------------- -}

      ThreadService::add_thread(p, daemon);

  {- -------------------------------------------
  (1) (トレース出力)
      ---------------------------------------- -}

      // Possible GC point.
      Events::log("Thread added: " INTPTR_FORMAT, p);
    }