code: public boolean toActive()
    {
      LifecycleState state;
      
      synchronized (this) {
        state = _state;
  
        if (state.isAfterActive() && ! state.isStopped()) {
          return false;
        }
        
        _state = ACTIVE;
  
        _lastChangeTime = CurrentTime.currentTime();
      }
  
      if (_log != null && _log.isLoggable(_level))
        _log.log(_level, "active " + _name);
  
      notifyListeners(state, ACTIVE);
      
      return true;
    }
docs: Changes to the active state.
  
  @return true if the transition is allowed