16、对Util.ArrayList描述正确的是()。
A. 集合被保证为不可变
B. 集合中的元素可按索引访问
C. 集合中的元素保证唯一性
D. 通过唯一的键访问集合中的元素
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根据中文填空,所填单词首字母已给出。注意动词形式。1.白天还算暖和,但晚上就冷得难受了。The days are still warm but the evenings are getting c__________.2.她阔步走上站台。She s___________ onto the platform.3.学生在考试期间的压力可能会非常大。The pressure on students during exam time can be i____________.4.如果孩子入睡困难,父母会疲惫不堪。A child's sleep problems cause parents f___________.5.每年秋天都有两百多万只野鸭迁徙到这个湖。More than 2 million wild ducks m__________ to the lake each fall.6.当他的举止开始变得怪异时,他的同事们起了疑心。Colleagues became s____________ when he started acting strangely.7.她不愿意对媒体说什么,这很容易理解。Her r_____________ to talk to the press was quite understandable.8.该研究项目持续了好几年。The research program s____________ over several years.9.刚才她还在那里,一会儿工夫就不见了。One moment she was there, and the next she had v____________.10.12岁以下的孩童乘坐公共交通工具时必须有成人陪伴。Children under 12 must be a______________ by an adult when travelling by public t
1、欲构造ArrayList类的一个实例,此类继承了List接口,下列方法( )是正确的。
ArrayList myList=new Object();
B. List myList=new ArrayList();
C. ArrayList myList=new List();
D. List myList=new List();
2、下面关于List集合的描述中,()是错误的。
A. List集合是有索引的
B. List集合可以存储重复的元素
C. List集合存和取的顺序一致
D. List集合没有索引
3、执行下面程序,其运行结果是( )。public class Example {public static void main( String[] args ){ArrayList list = new ArrayList(); //创建ArrayList集合list.add("Tom"); //向集合中添加字符串list.add("Jerry");Iterator it = list.iterator(); //获取迭代器it.next();it.next();System.out.println( it.next());}}
A. Tom
B. null
C. ""
D. 以上结果都错误