从用List给ArrayList赋值看容器的传值,最好用.addAll

        Integer[] arr = new Integer[] { 1, 40, -43, 2, -5, 76, 7 };  
        List list = new ArrayList();
        list = Arrays.asList(arr);
        ArrayList arrayList = new ArrayList();
        arrayList.addAll(list);//而不是直接用“=”赋值
        System.out.println(list);//[1, 40, -43, 2, -5, 76, 7]