求解答，方法和对象不能同时出现吗？

Question

Bus bus = new Bus(); bus.name = "汽车"; bus.people = 33; bus.size = 8; System.out.println("大小为"+bus.size+"的"+bus.name+bus.run()+bus.people+"人");run()是继承父类的，没毛病，运行后的报错是这样的：The operator + is undefined for the argument type(s) String, void看不太懂。