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[考试试题] JAVA认证历年真题:SCJP考试真题和解析一(5)

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发表于 2012-8-4 12:33:16 | 显示全部楼层 |阅读模式
3。B
# |# A& b1 \1 [3 Y5 z7 `+ L& ~) t请查阅JAVA类库。getID方法的返回值是“event type”。在认证考试中,总会有类似的书本以外的知识,这只能靠多实践来增长知识了。   4. Which statement about listener is true? # l9 K1 l$ q3 |0 ], ~  a
A. Most component allow multiple listeners to be added.
$ q! w1 o+ y: V( ~- x3 _) DB. If multiple listener be add to a single component, the event only affected one listener. : D: G1 @2 d4 m+ [
C. Component don?t allow multiple listeners to be add.
, Q1 c; {/ `2 K3 g* S# sD. The listener mechanism allows you to call an addXxxxListener method as many times as is needed, specifying as many different listeners as your design require. / y: L4 t5 ~* d6 {' p. X& Q
  4。A、D
% G& [' @. ^4 f, Y0 v; w控件可以同时使用多个“addXxxxListener”方法加入多个监听器。并且当多个监听器加入到同一控件中时,事件可以响应多个监听器,响应是没有固定顺序的。
! y5 P( [$ y9 A9 ?% }5.Give the following code: + f0 Y- ^7 n" i: [# {2 f
public class Example{
( N7 M4 {. v2 f/ W) R2 p0 V" ]: A$ ~3 Lpublic static void main(String args[] ){ 9 t" E2 K% f: K, q
int l=0;
/ F' v! B( b5 z! \2 ido{
% V+ F' L% C5 B1 m  v( M9 L+ V; @: `System.out.println(“Doing it for l is:”+l);
" p5 U0 P# y6 ?6 N}while(--l>0)
$ ?$ o: m/ l5 ]. c' E/ |6 QSystem.out.println(“Finish”); $ _) ]1 B' h5 i1 F4 I. B; x- h) Q
} % e4 M0 N% i7 [! C6 ]% ]4 k
}
, l3 \7 J  s' E5 `$ OWhich well be output: $ J- B# V0 |0 ^
A. Doing it for l is 3
* W2 ~+ S& G1 v6 JB. Doing it for l is 1 1 P" _9 O: x6 L4 I( H; \- k
C. Doing it for l is 2 $ U6 f8 |6 x4 Y2 f4 A- N
D. Doing it for l is 0
( o$ r( K0 ]5 }3 V/ j7 h2 LE. Doing it for l is ?C1
+ t7 ~8 G4 n5 Y% ~* w  n9 h0 zF. Finish
6 C# X: H- c4 D& Q. u, {& ~: N
  5。D、F 1 p5 w4 a& v) H* k+ g9 |
本题主要考察考生对流程控制的掌握情况。这是当型循环,条件为真执行,条件为假则退出。循环体至少执行一次,故会输出D。循环体以外的语句总会被执行,故输出F。
: Q: ^) r( `5 Y! D: o) ]0 b8 O. a  6. Give the code fragment: 8 F0 t$ a% ^- w5 U$ Y1 ?- z' }
1) switch(x){
- O7 K0 p9 \0 p# C4 q4 m$ S2 f5 b2) case 1:System.out.println(“Test 1”);break; ' q* f' z3 M9 Y. N7 u) D3 B2 w# e
3) case 2:
9 Q1 }5 i. H. q) h4) case 3:System.out.println(“Test 2”);break;
' x% }) d! v6 _, D# [3 I5) default:System.out.println(“end”);
) {, U3 S, z# B5 I( X6) } ! D* j0 F. t0 S. ^5 |
which value of x would cause “Test 2” to the output:
$ M( {5 ]0 V3 L* V" N5 VA. 1 7 N& N6 z5 Q0 @, E5 E
B. 2 5 ~- r" k1 e' i6 |* v# h2 F
C. 3
' d( x+ D4 l! k/ xD. default 5 {5 W; ]2 W  p3 n9 m
  6。B.C / D) A+ h6 w; a$ D
在开关语句中,标号总是不被当做语句的一部分,标号的作用就是做为条件判断而已,一旦匹配成功,就执行其后的语句,一直遭遇break语句为止。(包括default语句在内)3 O" e5 I5 w0 z2 o+ n
  7. Give incompleted method:
! h# e3 M6 v$ P9 f1)
8 B( D+ B( ^3 |' ], v+ p2) { if(unsafe()){//do something…}
/ a: _, I! P1 U2 ~6 Z6 ^% ?! ?3) else if(safe()){//do the other…}
" r( C: U" j5 k! t/ ]4) } 4 H5 n! [; K1 M" w  k
The method unsafe() well throe an IOException, which completes the method of declaration when added at line one?
$ c! D5 V* Y) O* r6 xA. public IOException methodName() # b$ R) l" b* \2 B% o/ A
B. public void methodName() 2 n4 W! ~8 A5 P: F
C. public void methodName() throw IOException
5 G2 e0 A, }$ w* H! M. @D. public void methodName() throws IOException
+ \$ n5 m3 |; ?+ Y' ?5 R7 IE. public void methodName() throws Exception
* {5 W2 a, H) R  s  7。D、F 0 ]7 J5 {/ P! s( `; C% I
IOException异常类是Exception的子类。根据多态性的定义,IOException对象也可以被认为是Exception类型。还要注意在方法声明中抛出异常应用关键字“throws”。 * B) c3 a1 K' h, r
  8. Give the code fragment:
+ s9 W* i! W  n( [! z. vif(x>4){ % W" I0 a; X) P
System.out.println(“Test 1”);} ) }0 ^; L, x5 s" |$ N% e1 P* b
else if (x>9){
: a4 C  y5 n! DSystem.out.println(“Test 2”);} # O$ b3 R+ u1 ?  F9 S2 G5 z
else {
6 }7 K- G. x# y9 D4 U: _2 X6 z* l, BSystem.out.println(“Test 3”);} 6 q' `% M3 L+ T, t+ r
Which range of value x would produce of output “Test 2”?
: ?9 H+ y0 y- H9 W+ q% `0 eA. x4
" X0 [) i6 x" q9 ^. AC. x>9 : [1 A: V) O, Y! m4 J% J8 n
D. None
! ?$ g% K$ c. \7 @: `; ?  8。D / t$ Q9 E$ ~1 [3 ?3 i& s
只有两种情况:大于4时输出“Test1”,小于等于4时输出“Test3”。 1 u$ t' \) v2 D" [9 B2 {4 t
  9. Give the following method:
3 ^( y3 P4 `  ~7 x" }) k! Xpublic void example(){
8 \3 f, C5 c7 I! \' W* Itry{ & q. Y1 t. r' l! i) x& V
unsafe(); 8 ~0 d, v7 Y/ ~; [  j" b
System.out.println(“Test1”); : A2 d6 a+ h$ [8 J  v( C& `
}catch(SafeException e){System.out.println(“Test 2”); 4 [9 v9 F: U% Q
}finally{System.out.println(“Test 3”);} ! a8 i3 Q& W: m9 L# W& R
System.out.println(“Test 4”);
' O$ c9 t4 ^6 J: A' O* N; QWhich will display if method unsafe () run normally?
" s6 h8 R4 l' S# sA. Test 1
' }; i& w( [8 I8 WB. Test 2
7 T2 l4 @# u! p: t/ sC. Test 3
( G" ^3 n9 s8 o: ^% T. bD. Test 4 + ~7 p7 Y5 o* ]; D' L
  9。A、C、D $ C9 {, B( _+ ^% Y+ I& [4 j
在正常情况下,打印Test1、Test3、Test4;在产生可捕获异常时打印Test2、Test3、Test4;在产生不可捕获异常时,打印Test3,然后终止程序。注意finally后面的语句总是被执行。
( T- ?1 s6 r6 ~; ?  10. Which method you define as the starting point of new thread in a class from which new the thread can be excution?
# e$ M7 a% N2 t/ j. m: C  [) y) l5 XA. public void start()
9 e1 g8 ]" Y, ~  d& RB. public void run()
" R% w  V( d+ R0 ]- T- rC. public void int() + f" B, Q' `  w4 K1 J
D. public static void main(String args[]) 0 E& K- z' g7 N1 |
E. public void runnable() 7 i' K  i, }9 ~" z: w0 q/ M
) B4 d; U" x! W. r' K- O
  10。B , H: p8 ^* I, f( h: w8 s
线程的执行是从方法“run( )”开始的,该方法是由系统调用的。程序员手工调用方法start(),使线程变为可运行状态
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