java选择题100题
一、选择
1、下面哪些是java语言中的关键字？
A.si z eof
B abstract
C NULL
D Native
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;
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);
在数据库中建立数据表System.out.println("The String No.5 is "+s5);
}
}
可爱的边框图片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
4、下面语句段的输出结果是什么？
int i = 9;
sw itch (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
二、多项选择
1、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);
2、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
java常见笔试题
E 2 and 2echarts地图迁移图
F 2 and 1
G 2 and 0
3、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];
字节与mb单位换算E int []a[] = new int[10][10];
JAVA笔试题选择题
1下面哪个是正确的类声明？假设每一段文本都做为一个名称为Fred.java的文件的全部内容？
a).
public class Fred{
public int x = 0;
public Fred (int x){
this.x=x;
}
}
b).
public class fred{
public int x = 0;
public Fred (int x){
this.x=x;
}
}
c).
public class Fred extends MyBaseClass, MyOtherBaseClass{
public int x = 0;
public Fred(int xval){
x=xval;
}
setaem
}
d).
protected class Fred{
private int x = 0;
private Fred (int xval){
x=xval;
}
}
A. a)
B. b)
C. c)
D. d)
2.在类设计中，类的成员变量要求仅仅能够被同一package下的类访问，请问应该使用下列哪个修辞词
A. protected
B. public

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