Given: What is the appropriate definition of the hashCode method in class Person?()
public class Pet{ private String name; public Pet(){ System.out.print(1); } public Pet(String name){ System.out.print(2); } } public class Dog extends Pet{ public Dog(String name){ //这里隐藏了一句代码:super.pet(); System.out.print(3); } } 执行new Dog(“棕熊”);后程序输出是哪项?()
class Animal{ Animal getOne(){return new Animal();}} class Dog extends Animal{ //insert code here } class AnimalTest{ public static void main(String[] args){ Animal[] animal={ new Animal(), new Dog()}; for(Animal a:animal){ Animal x= a.getOne(); } } } 和代码: 3a.Dog getOne() { return new Dog();} 3b.Animal getOne() { return new Dog();} 第3行中插入的哪项编译且运行无异常?
class ThreadExcept implements Runnable { public void run() { throw new RuntimeException("exception "); } public static void main(String [] args) { new Thread(new ThreadExcept()).start(); try { int x = Integer.parseInt(args[0]); Thread.sleep(x); System.out.print("main "); } catch (Exception e) { } } } 和命令行: java ThreadExcept 1000 哪一个是结果?()
Which two are true regarding a web application class loader?()
10. class Nav{ 11. public enum Direction { NORTH, SOUTH, EAST, WEST } 12. } 13. public class Sprite{ 14. // insert code here 15. } Which code, inserted at line 14, allows the Sprite class to compile?()
public class Yippee { public static void main(String [] args) { for(int x = 1; x < args.length; x++) { System.out.print(args[x] +“ “); } } } and two separate command line invocations: java Yippee java Yippee 1234 What is the result?()
public class Holt extends Thread{ private String sThreadName; public static void main(String argv[]){ Holt h = new Holt(); h.go(); } Holt(){} Holt(String s){ sThreadName = s; } public String getThreadName(){ return sThreadName; } public void go(){ Holt first = new Holt("first"); first.start(); Holt second = new Holt("second"); second.start(); } public void start(){ for(int i = 0; i < 2; i ++){ System.out.println(getThreadName() +i); try{ Thread.sleep(100); } catch(InterruptedException e){ System.out.println(e.getMessage()); } } } } 当编译运行上面的Java代码时,将会出现()。
If class Donkey2 is invoked twice, the first time without assertions enabled, and the second time with assertions enabled, what are the results?()
1. class MyThread implements Runnable { 2. public void run() { 3. System.out.print("go "); 4. } 5. 6. public static void main(String [] args) { 7. // insert code here 8. t.start(); 9. } 10. } 和如下四句: Thread t = new MyThread(); MyThread t = new MyThread(); Thread t = new Thread(new Thread()); Thread t = new Thread(new MyThread()); 分别插入到第5行,有几个可以通过编译?()