試題詳解

 1. import java.util.*； 

2. public class TestSet{ 

3. enum Example{ONE, TWO, THREE} 

4. public static void main(String[] args){

 5. Collection coll = new ArrayList()； 

6. coll.add(Example.THREE)；

 7. coll.add(Example.THREE)； 

8. coll.add(Example.THREE)；

 9. coll.add(Example.TWO)；

 10. coll.add(Example.TWO)；

 11. coll.add(Example.ONE)

 12. Set set = new HashSet(coll)； 

13. }

 14. } 

Which statement is true about the set variable on line 12?
(A) The set variable contains all six elements from the coll collection, and the order is guaranteed to be preserved.
(B) The set variable contains only three elements from the coll collection, and the order is guaranteed to be preserved.
(C) The set variable contains all six elements from the coll collection, but the order is NOT guaranteed to be preserved.
(D) The set variable contains only three elements from the coll collection, but the order is NOT guaranteed to be preserved.