2011年JAVA认证模拟题（13）

会计考友

　Q37. Which of the following are true about IO filters? 　　A Filters are supported on input, but not on output.
　　B Filters are supported by the InputStream/outputStram class hierarchy, but not by the Reader/Writer class hierarchy.
; o% ~# [9 F5 s, F% Q　　C Filters read from one stream and write to another.
　　D A filter may alter data that is read from one stream and written to another.
3 m; D  t3 o& J; d　　Q38 Which of the following are true?
　　A Only threads have locks.
' B6 x8 C6 r- }. Q( m. |　　B Classes have locks
. [+ {- a4 E, q0 E　　C Primitive types have locks.
, E2 d& i' J) A. c3 m" V! k' V; b　　D Only Runnable objects have locks.
　　Q39 What output does the following program display?
　　import java.util.*;
　　class Question {
　　public static void main (String args[]) ｝
+ R/ u0 r7 C  U. c) D　　String s1 = “abc”;

会计考友

</p>　　String s2 = “def”;
0 ]) q1 c5 G7 c) Q- f. C6 P8 \　　Stack stack = new Stack();
　　stack.push(s1);
; }) E; U: @" n! d5 I) ?; `# c　　stack.push(s2);
" D. G$ D0 a/ a3 Z* M, Q( j' t5 ?　　try {
　　String s3 = (String) stack.pop() +
* p, R' U* ^7 Y6 V7 o5 p4 N　　(String)stack.pop();
　　System.out.println(s3);
　　｝ catch(EmptyStackException ex) {
　　｝
4 x! x3 `2 R, F　　｝
　　｝
　　A abcdef
) l: F  o# Z1 n$ F$ E　　B defabc
' S  M) h4 c. b9 b　　C abcabc
　　D defdef
- r# j, b* Q! z+ R% T& n　　Q037 CD
5 O- g' [  \) T" a　　Q038 B
. X0 u3 ^4 s. z/ k　　Q039 B