123.txt

考试系统

ACD
1:20:50
Which interface does java.util.Hashable implement? 
A. java.util.Map 
B. java.util.List 
C. java.util.Hashable 
D. java.util.Collection 
** 
Given: 
1. public class X { 
2. public object m ()  { 
3. object o = new Float (3.14F); 
4. object [] oa = new object [1]; 
5. oa[0]= o; 
6. o = null; 
7. oa[0] = null; 
8.return o; 
9. } 
10. } 
When is the float object created in line 3, eligible for garbage collection? 
A. Just after line 5 
B. Just after line 6 
C. Just after line 7 
D. Just after line 8(that is, as the method returns) 
** 
Given: 
1. public class returnIt ( 
2. returnType methodA(byte x, double y) ( 
3. return (short) x/y * 2; 
4.     ) 
5. ) 
What is the valid returnType for methodA in line 2? 
A. int 
B. byte 
C. long 
D. double