After line 16.
After line 17.
After line 18 (when the methods ends).
There is no way to be absolutely certain.
The object is NOT eligible for garbage collection.
第1题:
1. public class X implements Runnable( 2. private int x; 3. private int y; 4. 5. public static void main(String[]args) 6. X that = new X(); 7. (new Thread(that)).start(); 8. (new Thread(that)).start(); 9. ) 10. 11. public void run() ( 12. for (;;) ( 13. x++; 14. y++; 15. System.out.printIn(“x=” + x + “, y = ” + y); 16. ) 17. ) What is the result?()
第2题:
10. class Line { 11. public static class Point { } 12. } 13. 14. class Triangle { 15. // insert code here 16. } Which code, inserted at line 15, creates an instance of the Point class defined in Line?()
第3题:
( 24 )请阅读下面程序
public class ThreadTest {
public static void main ( String args[ ]){
Thread t1 = new Thread ( new Hello ()):
Thread t2 = new Thread ( new Hello ()):
t l .start ():
t2.start ();
}
}
class Hello implements Runnable {
int i ;
public void run (){
while ( true ) {
System.out.println ( "Hello"+i++ ) ;
if ( i=5 ) break :
}
}
}
该程序创建线程使用的方法是()
A )继承 Thread 类
B )实现 Runnable 接口
C ) t l.start ()
D ) t2.start ()
第4题:
11. public static void append(List list) { list.add(”0042”); } 12. public static void main(String[] args) { 13. List
第5题:
12. void start() { 13. A a = new A(); 14. B b = new B(); 15. a.s(b); 16. b = null; 17. a = null; 18. System.out.println(“start completed”); 19. } When is the B object, created in line 14, eligible for garbage collection?()
第6题:
11. public static void main(String[] args) { 12. Object obj =new int[] { 1,2,3 }; 13. int[] someArray = (int[])obj; 14. for (int i: someArray) System.out.print(i +“ “) 15. } What is the result? ()
第7题:
11. static class A { 12. void process() throws Exception { throw new Exception(); } 13. } 14. static class B extends A { 15. void process() { System.out.println(”B”); } 16. } 17. public static void main(String[] args) { 18. new B().process(); 19. } What is the result?()
第8题:
10. public class ClassA { 11. public void count(int i) { 12. count(++i); 13. } 14. } And: 20. ClassA a = new ClassA(); 21. a.count(3); Which exception or error should be thrown by the virtual machine?()
第9题:
Which two code fragments will execute the method doStuff() in a separate thread?()
第10题:
public class Threads4 { public static void main (String[] args) { new Threads4().go(); } public void go() { Runnable r = new Runnable() { public void run() { System.out.print(”foo”); } }; Thread t = new Thread(r); t.start(); t.start(); } } What is the result?()