Sun Certified Programmer_310-035

QUESTION NO: 5
310 - 035
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-5 -
Given:
1. interface Animal {
2. void soundOff();
3. }
4.
5. class Elephant implements Animal {
6. public void soundOff() {
7. System.out.println(“Trumpet”);
8. }
9. }
10.
11. class Lion implements Animal {
12. public void soundOff() {
13. System.out.println(“Roar”);
14. }
15. }
16.
17. class Alpha1 {
18. static Animal get( String choice ) {
19. if ( choice.equalsIgnoreCase( “meat eater” )) {
20. return new Lion();
21. } else {
22. return new Elephant();
23. }
24. }
25. }
Which compiles?//意思是扏行哪一个能正常运行
A. new Animal().soundOff();
B. Elephant e = new Alpha1();
C. Lion 1 = Alpha.get(“meat eater”);
D. new Alpha1().get(“veggie”).soundOff();
Answer: D

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QUESTION NO: 6
Which statement is true?
A. Memory is reclaimed by calling Runtime.gc().
B. Objects are not collected if they are accessible from live threads.

/*意思是对象不被垃圾回收器收集，如果有活动的线程在防问。这是对的，因为的线程防问它就一定存在某一引用变量存储这个对象的引用值（句柄）*/
C. Objects that have finalize() methods are never garbage collected.
D. Objects that have finalize() methods always have their finalize() methods called before
the program ends.
E. An OutOfMemory error is only thrown if a single block of memory cannot be found
that is large enough for a particular requirement.
310 - 035
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-6 -
Answer: B

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QUESTION NO: 7
Given:
1. class A {
2. A() { }
3. }
4.
5. class B extends A {
6. }
Which two statements are true? (Choose two)
A. Class B’s constructor is public.
B. Class B’s constructor has no arguments.
C. Class B’s constructor includes a call to this().
D. Class B’s constructor includes a call to super().
Answer: B, D

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