Runnable接口中定义的唯一抽象方法是( )

A. sleep( )
B. start( )
C. begin( )
D. run( )

wait()方法、notify0及notifyAll()方法在下列哪个类或接口中

A. java.lang.Thread
B. java.lang.Object
C. java.lang.Runnable
D. java.lang.System

给定接口Runnable的定义，下面哪个语句创建了匿名内部类的实例（ ）

A. Runnable r=new Runnable(){ }
B. Runnable r=new Runnable(public void run(){});
C. Runnable r=new Runnable{public void run(){}};
D. Runnable r=new Runnable(){ public void run( ){ } };

有下面代码：Runnable task=new MyRunnable( );Thread myThread=new Thread(task);若上述代码能够正确编译，MyRunnable类应如何定义( )

A. public class MyRunnable extends Runnable{ public void run( ){ }}
B. public class MyRunnable Object Runnable{ public void run( ){ }}
C. public class MyRunnable implements Runnable{ public void run( ){ }}
D. public class MyRunnable implements Runnable{ public void start( ){ }}

下面的程序定义了一个线程PrintThread，该线程打印输出1～1000之间所有3的倍数，每输出一个数休眠1500毫秒，在main方法中创建了该线程的一个实例，并启动该线程。请将下面的程序填写完整。(答案中不要留不必要的空格）class PrintThread extends 【1】 {public PrintThread(String str) {【2】 ; // 调用父类的构造方法}public void run() {for(int i=1;i<=1000;i++) {if(i % 3 ==0)System.out.println(this.getName()+": "+i);try {【3】 ; // 休眠1500毫秒} catch (Exception e) { System.out.println(e.toString()); }}}}public class Exam4{public static void main(String[] args){PrintThread myThread = new PrintThread("PrintThread");【4】 ; //启动线程}}

以下程序是在一个对话框中的标签上显示当前的系统时间，若单击“结束”按钮则关闭对话框，请补充完整缺失的代码。import java.awt.*;import java.awt.event.*;import javax.swing.*;import java.util.Date;public class MyThread extends JDialog implements Runnable{JLabel lb=new JLabel();JButton bt=new JButton("结束");Date date=new Date();public MyThread(){setTitle("系统时钟");setLayout(new BorderLayout());add(lb,BorderLayout.CENTER);add(bt,BorderLayout.SOUTH);bt.addActionListener(new ActionListener(){【1】 {System.exit(0);}});setSize(200,200);【2】}public void run(){while(true){try{【3】date=new Date();lb.setText(date.toString());}catch(Exception e){}}}public static void main(String args[]){MyThread obj=new MyThread();Thread th=new Thread(obj);【4】}}

下列程序的功能是创建了一个显示5个“Hello!”的线程并启动运行，请将程序补充完整。publicclassThreadTestextends【1】 {publicstaticvoidmain(Stringargs[]){ThreadTestt=new 【2】 ;t.start();}publicvoidrun(){inti=0;while(true){System.out.println("Hello!");if(i++==4)break;}}}

读程序，写出正确的运行结果public class X extends Thread implements Runnable{public void run(){System.out.println("this is run()");}public static void main(String args[]) {Thread t=new Thread(new X());t.start();}}

读程序，写出正确的运行结果public class MyThread extends Thread {public MyThread(String name){super(name);}public void run(){System.out.println(this.getName());}public static void main(String args[]) {Thread t=new MyThread("MyThread");t.start();}}