JAVA考前模拟题与答案解析二

JAVA考前模拟题与答案解析(二)

JAVA试题及解答（二）2007-06-30 15

一、选择题

1、下面哪些是java语言中的关键字？

A sizeof

B abstract

C NULL

D Native

答：B

2、下面语句哪个是正确的？

A char='abc';

B long l=oxfff;

C float f=0.23;

D double=0.7E-3;

答：D

3、以下程序测试String 类的各种构造方法，试选出其运行效果。

class STR

{ public static void main(String args[])

{

String s1=new String();

String s2=new String("String 2");

char chars[]={'a',' ','s','t','r','i','n','g'};

String s3=new String(chars);

String s4=new String(chars,2,6);

byte bytes[]={0,1,2,3,4,5,6,7,8,9};

StringBuffer sb=new StringBuffer(s3);

String s5=new String(sb);

System.out.println("The String No.1 is "+s1);

System.out.println("The String No.2 is "+s2);

System.out.println("The String No.3 is "+s3);

System.out.println("The String No.4 is "+s4);

System.out.println("The String No.5 is "+s5);

}

}

A The String No.1 is The String No.2 is String 2 The String No.3 is a string

The String No.4 is string The String No.5 is a string

B The String No.1 is The String No.2 is String 2 The String No.3 is a string

The String No.4 is tring The String No.5 is a string

C The String No.1 is The String No.2 is String 2 The String No.3 is a string

The String No.4 is strin The String No.5 is a string

D 以上都不对

答：A

4、下面语句段的输出结果是什么？

int i = 9;

switch (i)

{ default:

System.out.println("default");

case 0:System.out.println("zero"); break;

case 1: System.out.println("one");

case 2: System.out.println("two");

}

A default

B default, zero

C error default clause not defined

D no output displayed

答：B

二、不定项选择题(在每小题的五个备选答案中选出正确答案，并将正确答案的序号填入题干后面的括号内，错

选多选，漏选均不得分。)

1、给出如下代码:

class Test

{

private int m;

public static void fun()

{ // some code...

}

}

如何使成员变量m 被函数fun()直接访问?

A、将private int m 改为protected int m

B、将private int m 改为public int m

C、将private int m 改为static int m

D、将private int m 改为int m

答: C

2、下面哪几个函数是public void example(){...}的重载函数？

A、public void example( int m){...}

B、public int example(){...}

C、public void example2(){...}

D、public int example ( int m, float f){...}

答: A，D

3、给出下面的代码段:

public class Base

{

int w,

x, y ,z;

public Base(int a,int b)

{ x=a; y=b;

}

public Base(int a, int b, int c, int d) { // assignment x=a, y=b w=d; z=c; }

}

在代码说明// assignment x=a, y=b处写入如下哪几个代码是正确的？

A、Base(a,b);

B、x=a, y=b;

C、x=a; y=b;

D、this(a,b);

答: C，D

4、已知如下定义：String s = "story"; 下面哪个表达式是合法的？

A、s += "books";

B、char c = s[1];

C、int len = s.length;

D、String t = s.toLowerCase();

答: A，D

5、Java中main()函数的值是什么?

A、String

B、int

C、char

D、void

答:D

6、如下哪些字串是Java中的标识符？

A、fieldname

B、super

C、3number

D、#number

E、$number

答：A,E

7、如下哪些是Java中有效的关键字？

A、const

B、NULL

C、false

D、this

E、native

答：A,C,D,E

8、如下哪些是Java中正确的整数表示?

A、22

B、0x22

C、022

D、22H

答: A,B,C

9、下面的代码段中，执行之后i 和j 的值是什么?

int i = 1;

int j;

j = i++;

A、1, 1

B、1, 2

C、2, 1

D、2, 2

答: C

10、下面句话是正确的?

A、>> 是算术右移操作符.

B、>> 是逻辑右移操作符.

C、>>> 是算术右移操作符

D、>>> 是逻辑右移操作符

答：A,D

11、下面哪个赋值语句是合法的？

A、float a = 2.0

B、double b = 2.0

C、int c = 2

D、long d = 2

答：B,C,D

12、下面哪个是main()函数的合法参数?

A、char args[]

B、char args[][]

C、String arg要[]

D、String args

答： C

13、下面哪个语句是创建数组的正确语句？

A、float f[][] = new float[6][6];

B、float []f[] = new float[6][6];

C、float f[][] = new float[][6];

D、float [][]f = new float[6][6];

E、float [][]f = new float[6][];

答：A,B,C,D

14、已知表达式int m[] = {0, 1, 2, 3, 4, 5, 6 }; 下面哪个表达式的值与数组下标量总数相等？

A、m.length()

B、m.length

C、m.length()+1

D、m.length+1

答：B

15、已知如下的命令执行java MyTest a b c 请问哪个语句是正确的？

A、args[0] = "MyTest a b c"

B、args[0] = "MyTest"

C、args[0] = "a"

D、args[1]= 'b'

答：C, D

16、已知如下代码：

public class Test

{

long a[] = new long[10];

public static void main ( String arg[] )

{ System.out.println ( a[6] );

}

}

请问哪个语句是正确的？

A、Output is null.

B、Output is 0.

C、When compile, some error will occur.

D、When running, some

error will occur.

答：B

17、已知如下代码：boolean m = true; if ( m == false ) System.out.println("False"); else

System.out.println("True"); 执行结果是什么？

A、False

B、True

C、None

D、An error will occur when running.

答： B

18、已知如下代码：public class Test { public static void main(String arg[]) { int i = 5; do {

System.out.println(i); } while (--i>5) System.out.println("finished"); } } 执行后的输出是什么？ A

、 5 B、4 C

、6 D、Finished E、None

答：A,D

19、下面代码执行后的输出是什么？outer: for(int i=0;i<3; i++) inner: for(int j=0;j<2;j++) { if

(j==1) continue outer; System.out.println(j+ "and "+i); }

A、0 and 0

B、0 and 1

C、0 and 2

D、1 and 0

E、1 and 1

F、1 and 2

G、2 and 0

H、2 and 1

I、2

and 2

答：A,B,C

20、已知如下代码：switch (m) { case 0: System.out.println("Condition 0"); case 1:

System.out.println("Condition 1"); case 2: System.out.println("Condition 2"); case 3:

System.out.println("Condition 3");break; default: System.out.println("Other Condition"); } 当m 的

值为什么时输出"Condition 2"?

A、0

B、1

C、2

D、3

E、4

F、None

答：A,B,C

21、当浏览器返回到新URL的包含applet 的页面时调用以下哪个函数？

A、init()

B、start()

C、stop()

D、destroy() 答：B

22、以下哪个方法用于定义线程的执行体？A、start() B、init() C、run() D、main() E、synchronized()

答：C

23、Java中如下哪个约束符是正确的? A、private B、public C、protected D、protect E、friend 答：

A,B,C

24如果类中的成员变量可以被同一包访问，则使用如下哪个约束符? A、private B、public C、protected D

、no modifier E、final 答：D

25、以下哪个约束符可用于定义成员常量？A、static B、final C、abstract D、No modifier can be used

答：B

26、如下哪个语句正确说明了native方法? A、public native void test(); B、public native void test

(){} C、public void native test(); D、public native test(){} 答：A

27、已知如下类说明：public class Test { private float f = 1.0; int m = 12; static int n=1;

public static void main(String arg[]) { Test t = new Test(); // some code... } } 如下哪个使用是正

确的？A、t.f B、this.n C、Test.m D、Test.n 答：A,D

28、已知如下代码：1: class Example{ 2: String str; 3: public Example(){ 4: str= "example"; 5: }

6: public Example(String s){ 7: str=s; 8: } 9:} } 10: class Demo extends Example{ 11: } 12:

public class Test{ 13:public void f () { 14:Example ex = new Example("Good"); 15:Demo d = new

Demo("Good"); 16:} } 哪句语句会导致错误？A、line 3 B、line 6 C、line 10 D、line 14 E、line 15

答：E

29、已知如下类定义：class Base { public Base (){ //... } public Base ( int m ){ //... }

protected void fun( int n ){ //... } } public class Child extends Base{ // member methods } 如下

哪句可以正确地加入子类中？A、private void fun( int n ){ //...} B、void fun ( int n ){ //... } C

、protected void fun ( int n ) { //... } D、public void fun ( int n ) { //... } 答：C,D

30、如下哪个语句是正确的？A、In Java single inheritance is allowed, which makes code more

reliable. B、A subclass inherits all methods ( including the constructor ) from the superclass. C

、 A class can implement as many interfaces

as needed. D、When a class implements an interface,

it can define as many methods of the interface as needed. 答：A,C

31、在如下源代码文件Test.java中, 哪个是正确的类定义？

A、public class test { public int x = 0; public test(int x) { this.x = x; } }

B、public class Test{ public int x=0; public Test(int x) { this.x = x; } }

C、public class Test extends T1, T2 { public int x = 0; public Test (int x) { this.x = x; } }

D、public class Test extends T1{ public int x=0; public Test(int x){ this.x = x; } }

E、protected class Test extends T2{ public int x=0; public Test(int x){ this.x=x; } }

答：B,D

32、Person, Student 和Teacher 都是类名。这些类有以下继承关系。Person | --------------- | |

Student Teacher 并且在Java源代码中有如下表达式：Person p = new Student(); 如下哪个语句是正确的？

A、The expression is legal.

B、The expression is illegal.

C、Some errors will occur when compile.

D、Compile is correct but it will be wrong when running.

答：A

33、当Frame改变大小时，放在其中的按钮大小不变，则使用如下哪个layout?

A、FlowLayout

B、CardLayout

C、North and South of BorderLayout

D、East and West of BorderLayout

E、GridLayout 答：D

34、当Frame改变大小时，放在其中的按钮大小不变，则使用如下哪个layout? A、FlowLayout B、CardLayout

C、North and South of BorderLayout

D、East and West of BorderLayout

E、GridLayout 答：A

35、如下哪个方法可以从WindowEvent获取事件源? A、getFrame() B、getID() C、getSource() D、

getWindow() 答：C,D

36、以下哪个有关事件监听器的语句是正确的？A、Multiple listeners can be attached to one

component. B、Only one listener can be attached to one component. C、One listener can receive and

process the events from multiple components. D、One listener can receive and process the events

from only one component. 答：A,C

37、监听器接口的方法返回值是什么？A、int B、String C、void D、Object E、AWTEvent 答：C

38、下面哪个事件监听器在Java中有事件适配器? A、MouseListener B、KeyListener C、ActionListener D

、ItemListener E、WindowListener 答：A,B,E

39、下面哪个方法与applet的显示无关? A、update() B、draw() C、repaint() D、paint() 答：B

40、已知如下说明：TextArea ta = new TextArea ("Hello", 5, 5); 请问哪个语句是正确的？

A、The

maximum number of characters in a line is 5. B、The displayed height is 5 lines otherwise constrain. C、The displayed string can use multiple fonts. D、The displayed strings are editable.

答：B,D

41、请问如下哪个方法可以将MenuBar加入Frame中? A、setMenu() B、setMenuBar() C、add() D、

addMenuBar() 答：B

42、下面哪个不是Java中的容器? A、ScrollPane B、Canvas C、Scrollbar D、Applet E、Dialog 答：B,C

43、下

面哪个方法可用于定义新线程类？

A、implement the Runnable interface

B、add a run() method in the class

C、create an instance of Thread

D、extend the Thread class

答：A,D

44、下面哪个stream是node流?

A、FileInputStream

B、BufferedInputStream

C、PushbackInputStream

D、ByteArrayInputStream 答：A,D

45、哪个类可用于处理Unicode? A、InputStreamReader B、BufferedReader C、Writer D、

PipedInputStream 答：A,B

46、下面哪些语句能够正确地生成5个空字符串？ A String a[]=new String[5]; for(int

i=0;i<5;a[++]

=""); B String a[]={"","","","",""}; C String a[5]; D String[5]a; E String []a=new String[5];

for( int i=0;i<5;a[i++]=null);

答：A，B

47、下面哪些选项将是下述程序的输出？public class Outer{ public static void main(String

args[]){ Outer: for(int i=0; i<3; i++) inner:for(int j=0;j<3;j++){ if(j>1)

break; System.out.println(j+"and"+i); } } } A 0 and 0 B 0 and 1 C 0 and 2 D 0

and 3 E 2 and 2 F 2 and 1 G 2 and 0

答：A，B，C

48、下面哪个语句正确地声明一个整型的二维数组？

A int a[][] = new int[][];

B int a[10][10] = new int[][];

C int a[][] = new int[10][10];

D int [][]a = new int[10][10];

E int []a[] = new int[10][10];

答：C，D，E

三、编程题1、编写一个程序，用选择法对数组a[]={20,10,50,40,30,70,60,80,90,100}进行从大到小的排序

。编程题答案

public class ArraySort

{

public static void main(String args[])

{

int array[]={20,10,50,40,30,70,60,80,90,100};

int i,j,k,t;

int l=array.length;

for(i=0;i

{

k=i;

for(j=i+1;j

if(array[j]

t=array[k];array[k]=array;array=t;

}

for(i=0;i

System.out.println("array["+i+"]="+array);

}

}