if (unit == null) { Log.warn("in Array.addUnit(), the Unit passed in is null"); return null; }
  public Unit addUnit(Unit unit) {    if (unit == null) {      Log.warn("in Array.addUnit(), the Unit passed in is null");      return null;    }    Units u = getUnits();    if (u == null) {      u = new Units();      setUnits(u);    }    return  u.addUnit(unit);  }