java软件工程师笔试题目(III) 规则: 1. 时间:40分钟 2. 个人独立完成,不能使用手机等上网上查询。如果被发现作弊,则零分。 3. 为了环保和节约纸张,请在答题卡上填写答案 一、不定项选择题(每题5分) Question 1 Given: 11. public class Test {
, V' U! S# [( v. }/ t8 o12. public static void main(String [] args) {
0 q% m* g- o! `; K' n13. int x =5; B6 c9 }) B2 s W
14. boolean b1 = true; : F6 S! O2 g# |
15. boolean b2 = false;
* N V; K4 r& ^2 N8 G17.if((x==4) && !b2) 3 v( v) N" |" e1 K
18. System.out.print(”l “); # B6 [5 y& b) K3 L
19. System.out.print(”2 “);
8 b. U- p2 k/ ?, z/ T20. if ((b2 = true) && b1) . J6 ]0 ^6 [; w( u* |2 x( Q
21. System.out.print(”3 “);
) ^- V m) I% o$ D" H* O! P22. } + g1 B+ w. U5 x1 r; S
23. } ( D. D7 s! o6 ?) ?0 F. m3 A- f! E
What is the result?
1 Y2 P. S3 t$ ^A. 2
4 t6 c! O, b# v RB. 3 ; N; B, T7 I, \! [0 T
C. 1 2 1 ^1 w8 _. ~+ z* y
D. 2 3 0 b$ {* f; V1 ^0 `( `- P; H
E. 1 2 3 1 L$ Q4 _7 Q6 H; e
F. Compilation fails. : y u9 O% |% z5 x9 I
G. Au exceptional is thrown at runtime. Question 2 Assume that country is set for each class. Given: 10. public class Money {
# }* w( H) p! X9 L% s) A5 E11. private String country, name;
; G. X3 ^8 q, ?4 |5 F12. public String getCountry() { return country; }
+ Z" F, ^4 ]( U13.} and: 24. class Yen extends Money {
: Z; Y g' L8 l' Q. x( `25. public String getCountry() { return super.country; }
) W3 d% t+ g$ }7 h26. } - \, P6 p/ o4 o5 B4 E: L, O+ C% L; j) r
27. 7 N- Y! L' J9 V( ~ A" q
28. class Euro extends Money { ( E& C1 J$ a) P0 `$ G7 s
29. public String getCountry(String timeZone) { ( O/ t8 @5 p$ ?. o d- ~, t/ C
30. return super.getCountry();
0 Y+ Y* v$ M r31. } ; m& \9 {; a3 W6 @* n
32. }
' @9 n2 Y, F1 r) ~& k% i& a' n" vWhich two are correct? (Choose two.) A. Yen returns correct values.
+ f: u8 u8 g- r# W4 P! u$ jB. Euro returns correct values.
' V. p7 o& s! n; }% w2 f9 l/ LC. An exception is thrown at runtime. 5 D7 w% r9 d& p# B4 J
D. Yen and Euro both return correct values. + P: b0 U7 u9 Y* m
E. Compilation fails because of an error at line 25. $ q1 r5 g5 V; K1 v7 X% @! X
F. Compilation fails because of an error at line 30. Question 3 Given: 1. class TestA {
- d" k5 |5 J8 C4 V/ X2 v; j6 G2. public void start() { System.out.println(”TestA”); } 7 T4 I6 `7 Z4 C7 }) Q! n7 ?
3. }
0 u& Z/ Y. d5 p( _4 o5 K4. public class TestB extends TestA { , Z& h0 \$ `4 p3 r
5. public void start() { System.out.println(”TestB”); }
4 G* i( H2 l! W4 k9 v6. public static void main(String[] args) {
; w* y1 s* b3 |; A7. ((TestA)new TestB()).start(); ) f9 L! g- F3 O$ K+ A H
8. } % I- A1 K& r6 O* L( ?# o( I
9. } , U+ p$ o. d7 ]
What is the result? A. TestA
- a0 `& Z4 T3 m- }B. TestB
5 L* ~) e! H" ~' V A1 ?: wC. Compilation fails.
: ]& B+ K5 N3 k# w0 S/ lD. An exception is thrown at runtime. Question 4 Given: 11. public static void main(String[] args) { 5 b5 f3 W0 J' [, C: i7 a
12. String str = “null’; ' F- @7 s; g3 @5 I% j& j* J, O1 g
13. if (str == null) {
" ^, y, I2 C }3 y* [- a2 l14. System.out.println(”null”); . ~9 Z7 B* T# b( R
15. } else (str.length() == 0) { $ R S& N* d! G3 i) R& H
16. System.out.println(”zero”);
: a' N# I1 l% H9 V17. } else {
2 A5 @3 `$ q1 P5 q. i i& j18. System.out.println(”some”); ! d' |; B; o3 s% j0 N
19. } - v- Z }; f Y% G9 n
20. }
) `: A8 e& A/ d* x‘What is the result? A. null
$ Z Z7 \' a3 m7 fB. zero 8 D6 \& S4 h, K! q1 u- b
C. some
! q x0 n' J% E; s! Q0 BD. Compilation fails. + `- V5 ^1 F/ r& }% t6 } E
E. An exception is thrown at runtime. Question 5 Given: 33. try { # I+ i& A8 ]2 o
34. // some code here
% X8 O8 `9 B- ^$ `' f9 ]35. } catch (NullPointerException e1) { # y! Q8 v5 Y' [; e: h% L$ H, `
36. System.out.print(”a”); & N r- n4 `( T' B& k9 n
37. } catch (RuntimeException e2) { . P* P4 F7 y5 P+ Z6 J
38. System.out.print(”b”); 5 @: Z2 w# n ?5 U( X. P, `
39. } finally { ' p! [9 I- \7 f/ L, n1 |
40. System.out.print(”c”); 4 `& V" `* r% g2 l. u
41. } & ~7 X4 d& q0 c
What is the result if a NullPointerException occurs on line 34? ! R# @4 A1 I n5 U j7 O
A. c
3 x9 V* l0 P9 {B. a # ~; H. z4 H( s
C. ab
! J" U$ E5 T3 Q. a: yD. ac 6 D4 q: _1 U& _7 X% ^6 X) c
E. bc 2 \3 Y& w& s$ t6 K. a
F. abc Question 6 Given this method in a class: 21. public String toString() { 0 a( P K' \8 F$ z8 L3 [
22. StringBuffer buffer = new StringBuffer();
% x: \. D, [# Y, V# s0 U23. buffer.append(’<’);
# v7 v- o6 r3 P' H& `4 m) @- `24. buffer.append(this.name);
( E) Z, m" v. n0 f+ T; F25. buffer.append(’>’); ! ?* D( `! O7 g b" a, ^' u
26. return buffer.toString();
* W7 h" |9 v' ~" G' S27. } 8 q1 k6 Y" L/ E$ e& s# K
Which is true? A. This code is NOT thread-safe.
2 @7 u3 T! k6 V* `! C% g1 j/ TB. The programmer can replace StringBuffer with StringBuilder with no 8 W7 c; G3 {- h+ F1 P
other changes.
8 n- B4 U* \ Z, C n$ l4 [4 o p1 EC. This code will perform well and converting the code to use
% g& \* ~, T2 m& A( j% x* sStringBuilder will not enhance the performance.
( E" W* X4 ]3 |D. This code will perform poorly. For better performance, the code
$ k9 m! Z# S1 k! g4 @$ a3 h j( W# Yshould be rewritten: return “<“+ this.name + “>”; Question 7 Given: 11. String test= “a1b2c3”; " _, k- o% B2 j& l+ P P
12. String[] tokens = test.split(”\\d”);
$ u/ ?) e) E9 T( ?) H4 f13. for(String s: tokens) System.out.print(s +“ “);
6 _8 }, e0 Z/ p- d1 dWhat is the result?
* O ?" l3 Y" s) }( |A. a b c 2 ^& E' V* ~0 M- Q! [4 }
B. 1 2 3
3 a% d9 [0 Z) i( d; M7 XC. a1b2c3 ' \8 c4 _; U7 f8 w1 }" x
D. a1 b2 c3
8 W3 u* f) W& E0 J( h; C$ A, S* R! sE. Compilation fails. , J! Q# Q/ i( C q4 Z t2 A
F. The code runs with no output. ; U$ Y" P( ^* @
G. An exception is thrown at runtime. Question 8 Question 9 Question 10 请选择同向的图形: Question 11 Question 12 表USER_INFO的结构如下: 下面那些选项可以插入一行到该表中: A、INSERT INTO USER_INFO(USER_INFO_ID, USER_NAME, PASSWORD) VALUES(null,'BQ','password'); B、INSERT INTO USER_INFO VALUES('helloword_id','BQ','password'); C、INSERT INTO USER_INFO(USER_INFO_ID) VALUES('helloword_id'); D、INSERT INTO USER_INFO(USER_INFO_ID, USER_NAME, PASSWORD) VALUES('helloword_id','BQ','password'); Question 13 下面关于视图说法正确的是: A、一个视图可以作为只读被创建。 B、一个视图可以用来连接两个或者更多的表而创建。 C、一个视图在select语句中不能有一个order by 语句。 D、一个视图在select语句中不能同group by 语句一起创建。 E、一个视图必须在select语句中为列名定义别名。 Question 14 EMPLOYEES表数据如下: 选择下面正确的选项: A、SELECT * FROM EMPLOYEES WHERE SALARY>(SELECT MIN(SALARY) FROM EMPLOYEES GROUP BY DEPARTMENT); B、SELECT * FROM EMPLOYEES WHERE SALARY>(SELECT MIN(SALARY) FROM EMPLOYEES GROUP BY DEPARTMENT); C、SELECT * FROM EMPLOYEES WHERE SALARY>(SELECT MIN(SALARY) FROM EMPLOYEES); D、SELECT * FROM EMPLOYEES WHERE SALARY>ALL(SELECT SALARY FROM EMPLOYEES); Question 15 STUDENTS表为空表,添加主键STUDENT_ID列,那个选项能完成这个任务: A、ALTER TABLE STUDENTS ADD PRIMARY KEY STUDENT_ID; B、ALTER TABLE STUDENTS ADD CONSTRAINT PRIMARY KEY (STUDENT_ID); C、ALTER TABLE STUDENTS ADD CONSTRAINT STUD_ID_KEY PRIMARY KEY (STUDENT_ID); D、ALTER TABLE STUDENTS ADD CONSTRAINT STUD_ID_KEY PRIMARY KEY STUDENT_ID; Question 16 一个学生只能就读于一个班级,而一个班级可以同时容纳多个学生,学生与班级之间是()的关系。 A、一对一 B、一对多 C、 多对一 D、多对多 : @1 H. }' g4 C' M, q
|