Java認(rèn)證考試章節(jié)練習(xí)(2018.07.27)

package com.company.application； 
public class MainClass { 
public static void main（String[] args） { } 
} 
And MainClass exists in the /apps/com/company/application directory. Assume the CLASSPATH environment variable is set to “.“ （current directory）. 
Which two java commands entered at the command line will run MainClass？（）

11. public enum Title { 
12. MR（”Mr.”）， MRS（”Mrs.”）， MS（”Ms.”）； 
13. private final String title； 
14. private Title（String t） { title = t； } 
15. public String format（String last， String first） { 
16. return title + “ “ + first + “ “ + last； 
17. } 
18. } 
19. public static void main（String[] args） { 
20. System.out.println（Title.MR.format（”Doe”， “John”））； 
21. } 
What is the result？（） 

1. public class GC { 
2. private Object o； 
3. private void doSomethingElse（Object obj） { o = obj； } 
4. public void doSomething（） { 
5. Object o = new Object（）； 
6. doSomethingElse（o）； 
7. o = new Object（）； 
8. doSomethingElse（null）； 
9.o=null； 
10. } 
11. } 
When the doSomething method is called， after which line does the Object created in line 5 become available for garbage collection？（）