java复习题.doc

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
2、下面语句哪个是正确的?
A char = 'abc'; B long l = 0xfff; C float f = ; D double = -3;
3、下列不可作为java语言修饰符的是()
A a1 B $1 C _1 D 11
4、有一段java应用程序,它的主类名是a1,那么保存它的源文件名可以是()
A B C a1 D都对
5、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);
("The String is "+s1);
("The String is "+s2);
("The String is "+s3);
("The String is "+s4);
("The String is "+s5);
}
}
A The String is
The String is String 2
The String is a string
The String is string
The String is a string
B The String is
The String is String 2
The String is a string
The String is tring
The String is a string
C The String is
The String is String 2
The String is a string
The String is strin
The String is a string
D 以上都不对
6、下面语句段的输出结果是什么?
int i = 9;
switch (i) {
default:
("default");
case 0:
("zero");
break;
case 1:
("one");
case 2:
("two");
}
A default B default, zero
C error default clause not defined D no output displayed
7、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被方法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
8、下面说法正确的是()
A java Applet程序必须在浏览器中执行
B java 应用程序必须在浏览器里执