2011年JAVA认证模拟题第二阶段（19）

会计考友

　　Q55.What is wrong with the following code?
　　1. final class First {
　　2. private int a = 1;
2 ~' s% j/ }3 u　　3. int b = 2;
　　4. ｝
　　5. class Second extends First {
$ @/ y2 P& O0 h( O$ G1 a　　6. public void method() {
　　7. System.out.println(a+b);
　　8. ｝
  D6 e  p6 X  u( m. f- x, [　　9. ｝
　　a. You cannot invoke println() without passing it a string.
　　b. Because a is private, no classes other than First can access it.
- I' g2 s+ y" \　　c. Second cannot extend First.
$ T- f/ c9 U. ^. Y4 w, B0 c% ]　　d. final is not a valid keyword for a class.
' a. r& O9 \: d. L　　Q56.What is displayed when the following piece of code is executed.
　　1. class Test extends Thread {
　　2. public void run() {
　　3. System.out.print(“1 “);
# z( C4 O9 E: `1 z1 l6 q% x' ^# B　　4. yield();
　　5. System.out.print(“2 “);
. n7 T/ p2 C, Z6 {) ~0 Y3 \/ c　　6. suspend();
　　7. System.out.print(“3 “);

) p1 q% E2 S3 y; o1 {- M/ M( T$ K　　8. resume();

会计考友

</p>　　9. System.out.print(“4 “);
+ ?8 B- d6 j2 p, n! n. E　　10. ｝
; `9 f1 N2 [4 K% C* X　　11 public static void main(String []args) {
　　12. Test t = new Test();
  u. ~# y) j2 j# O% K( Q　　13. t.start();
　　14. ｝
　　15. ｝
　　a. Nothing, this is not a valid way to create and start a thread.
　　b. 1 2
& o7 C6 u( i* b% @5 y0 B( S　　c. 1 2 3
  M  ~8 L( W: k" j& m8 q0 ]　　d. 1
　　Q57.What must be true for the RunHandler class so that the instances of RunHandler can be used as written in the following code?
　　1. class Test {
1 G9 G" c; g1 ]! o6 {3 Z: [　　2. public static void main(String args[]){
　　3. Thread t = new Thread(new RunHandler());
　　4. t.start();
　　5. ｝
! K$ \! s, _# c' s% Y+ S　　6. ｝
　　Select all valid answers ?
　　a. RunHandler must only implement the java.lang.Runnable interface.
　　b. RunHandler must only extend the Thread class.
% R1 w5 g- F- k, ?+ i　　c. RunHandler must extend the Thread class or implement Runnable interface.
, g& S9 A1 |+ h　　d. RunHandler must provide a run() method declared as public and returning void.
5 i+ O# G0 m/ c$ Z) j7 [　　55. c
$ r0 ]5 U0 k2 [- y3 K　　56. b
　　57. cd