多项选择题
ArraryList a = new ArrayList();
a.add(“Alpha”);
a.add(“Bravo”):
a.add(“Charlie”);
a.add(“Delta”);
Iterator iter = a.iterator();
Which two, added at line 17, print the names in the ArrayList in alphabetical order?()
A. for (int i=0; i< a.size(); i++) System.out.println(a.get(i)));
B. for (int i=0; i< a.size(); i++) System.out.println(a[i]);
C. while( iter.hasNext() ) System.out.println(iter.next()) ;
D. for (int i=0, i< a.size(); i++) System.out.println(iter[i]);
E. for (int i=0; i< a.size(); i++) System.out.println(iter.get(i));
相关考题
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单项选择题
Whatcancauseathreadtobecomenon-runnable?()
A. Exiting from a synchronized block.
B. Calling the wait method on an object.
C. Calling the notify method on an object.
D. Calling the notifyAll method on an object. -
单项选择题
public class A extends Thread { A() { setDaemon(true); } public void run() { (new B()).start(); try { Thread.sleep(60000); } catch (InterruptedException x) {} System.out.println(“A done”); } class B extends Thread { public void run() { try { Thread.sleep(60000); } catch (InterruptedException x) {} System.out.println(“B done”); } } public static void main(String[] args) { (new A()).start(); } } What is the result?()
A. A done
B. B done
C. A done B done
D. B done A done
E. There is no exception that the application will print anything.
F. The application outputs “A done” and “B done”, in no guaranteed order. -
单项选择题
public class X implements Runnable { private int x; private int y; public static void main(String [] args) { X that = new X(); (new Thread( that )).start(); (new Thread( that )).start(); } public void run() { for (;;) { synchronized (this) { x++; y++; } System.out.println(Thread.currentThread().getName() + “x = “ + x + “, y = “ + y); } } } What is the result?()
A. Compilation fails.
B. The program prints pairs of values for x and y that might not always be the same on the same line (for example, “x = 2, y = 1”).
C. The program prints pairs of values for x and y that are always the same on the same line (for example, “x = 1, y = 1”). In addition, each value appears only once (for example, “x = 1, y = 1” followed by “x = 2, y = 2”). The thread name at the start of the line shows that both threads are executing concurrently.
D. The program prints pairs of values for x and y that are always the same on the same line (for example, “x = 1, y = 1”). In addition, each value appears only once (for example, “x = 1, y = 1” followed by “x = 2, y = 2”). The thread name at the start of the line shows that only a single thread is actually executing.
