2011年JAVA认证模拟题第二阶段（24）

会计考友

　　Q70.What kind of stream is the System.out object?
$ X$ Z5 X* |: d3 F- U! {　　a. java.io.BufferedWriter
　　b. java.io.PrintStream
; _+ E+ a+ \* w' G& }$ Z# S- o5 j　　c. java.io.FileWriter
% q! O* x1 Q' M4 X/ \　　d. java.io.OutputStreamWriter
% S9 z. w' G' `- n6 G) u! H, @　　Q71.Which of the following events has a matching adapter class that implements the appropriate listener interface? Select all correct answers.
　　a. java.awt.event.MouseEvent
! b* w+ n8 m! s9 K1 {. r8 @　　b. java.awt.event.ActionEvent
. K# p- {0 N$ G! q　　c. java.awt.event.FocusEvent
　　d. java.awt.event.ItemEvent
, w. W! }$ g* z8 E* S& _　　Q72.Here is a partial listing of a class to represent a game board in a networked game. It is desired to prevent collisions due to more than one Thread using the addPic method to modify the array of Image references.
3 Y6 y3 P- o$ \% @) A% Q* _  M/ b# J　　1. class Board extends Object {
+ \) \* f4 J% `4 g# f( X! i& J　　2. Image[] pics = new Image[64];
% ~4 x$ P& ?+ a　　3. int active = 0;
; s9 W# d! K7 g2 f. ~0 j9 s　　4. public boolean addPic( Image mg, int pos) {
　　5. synchronized (this) {
- c3 a; B) ^" E/ A+ R　　6. if (pics[pos] == null)
　　7. { active++ ; pics[pos] = mg; return true; ｝
$ x% `. Q, G+ v. `* g　　8. else
　　9. return false;
; G& V) v% f& t/ V! n　　10. ｝
　　11. ｝
% B% S5 R; h! T　　12. // remainder of class
2 |! ~1 c$ |$ X8 |  h0 M, m　　Select all the alternatives for line 5 that would accomplish this.
　　a. synchronized (this)
　　b. synchronized (pics)
　　c. synchronized (mg)
8 H. J& R" C/ ?! o9 L: P+ t; _　　d. synchronized (active)
　　70. b
　　71. ac
* y/ E4 f  H4 k( N. Z! `: M  r　　72. ab