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reverse(list)返回的是Iterator,当然编译不过了,
11. public static Iterator reverse(List list) {
12. Collections.reverse(list);
13. return list.iterator();
14. }
15. public static void main(String[] args) {
16. List list = new ArrayList();
17. list.add(“ 1”); list.add(“2”); list.add(“3”);
18. for (Object obj: reverse(list)) // 出错了 Can only iterate over an array or an instance of java.lang.Iterable
// 这里要求是一个对象:数组(集合)这是JDK 1.5 for 新特性
19. System.out.print(obj + “,”);
20. }
!(R)What is the result?
A. 3,2, 1,
B. 1, 2, 3,
C. Compilation fails.
D. The code runs with nooutput.
E. An exception is thrown at runtime.
Answer: C