Compilation fails.
aAaA aAa AAaa AaA
AAaa AaA aAa aAaA
AaA AAaa aAaA aAa
aAa AaA aAaA AAaa
An exception is thrown at runtime.
第1题:
下列Java源程序结构中前三种语句的次序,正确的是
A.import, package, public class
B.import必为首,其他不限
C.public class, import, package
D.package, import, public class
第2题:
在下面Java Applet程序的下画线处填入代码,使程序完整并能够正确运行。
import java.applet.*;
import java.awt.*;
public class HelloWorld ______ {
public void paint(Graphics g) {
g.drawString("Hello World!",25,25);
}
}
第3题:
下列程序片段中,能通过编译的是
A.public abstract class Animal{ public void speak();}
B.public abstract class Animal{ public void speak(){}}
C.public class Animal{ public abstract void speak();}
D.public abstract class Animal{ public abstract void speak(){}}
第4题:
下列哪个选项的java源文件程序段是不正确的? ( )
A.package testpackage; public class Test{ }
B.import java.io.*; package testpackage; public class Test{ }
C.import java.i.*; class Person{} public class Test{ }
D.import java.io.*; import java.awt.*; public class Test { }
第5题:
请将下面的Applet程序补充完整。
import java. awt. *;
import java. applet. *;
public class Hi【 】{
public void paint(Graphics g){
g. drawString("Hi!", 25, 25);
}
}
第6题:
将下面Applet程序补充完整。
import java.awt.*:
import java.apptet.*;
public class Hi ______ {
public void paint(Graghics g) {
g.drawstring("Hi!",2.5,2.5);
}
}
第7题:
下列哪个选项的java源文件代码片段是不正确的?
A.package testpackage; public class Test{ }
B.import java. io. *; package testpaekage; public class Test { }
C.import java.io.*; class Person { } public class Test { }
D.import java.io.*; import java. awt.*; public class Test{ }
第8题:
设有如下程序: import java.util.*; public class Sun { public static void main(String args[ ]) { int score; String a; Random r=new Random(); score=r.nextInt(4)+5; switch(score) { case 0: a="E"; break; case 1: a="D"; break; case 2: a="C"; break; case 3: a="B"; break; default: a="A"; } System.out.println(A) ; } } 程序运行的结果是( )。
A.a="A"
B.aa"E" a="A"
C.a="E"
D.a="C"
第9题:
从对象流中读取对象,请在下面横线处填写代码完成此程序。
import java.util. *;
import java. io. *;
public class UnSerializeDate
{
date d = null;
UnSerializeDate ( )
{
try
{
FileInputStream f1 = new FileInputStream("date.ser");
d = (Date) s. readobject ();
f1,close();
}
catch (Exceptin e)
{
e. printStackTrace ();
}
}
public static main(String args [] )
{
System.out.println("The date read is: "+ a.d.toString());
}
}
第10题:
本题的功能是获取鼠标在窗口中的位置。当鼠标移进窗口中,就会实时显示鼠标在窗口中的相对位置,比如显示为"鼠标的当前位置:X:Y"(其中,X为横坐标,Y为纵坐标)。
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
public class java2
{
public static void main(String[]args)
{
MouseFrame. frame=new MouseFrame();
frame.setDefaultCloseoperation(JFrame.EXIT_
0N CLOSE);
frame.show();
}
}
class MouseFrame. extends JFrame
{
public MouseFrame()
{
setTitle("java2");
setSize(WIDTH,HEIGHT);
MousePanel panel=new MousePanel();
Container contentPane=getContentPane();
contentPane.add(panel);
}
public static final int WIDTH = 300;
public static final int HEIGHT=200;
}
class MousePanel extends JPanel
{
public MousePanel()
{
addMouseListener(new MouseHandler());
addMouseMotionListener(new MouseMotionHan-
dler());
}
public void paintComponent(Graphics g)
(
super.paintComponent(g);
String text="鼠标指针位置:"+mousex+":"
+mousey;
g.drawString(text,10,10);
}
private int mousex,mousey;
private class MouseMotionHandler {
public void mouseMoved(MouseEvent event)
{
mousex=event.getX();
mousey=event.getY();
repaint();
}
public void mouseDragged(MouseEvent event)
{
mousex=event.getX();
mousey=event.getY();
repaint();
}
}
private class MouseHandler
{
public void mousePressed(MouseEvent eveat)
{mousex=event.getX();
mousey=event.getY();
}
}
}