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;
责任编辑：cyth
