Java OCA OCP Practice Question 2854

Question

What is the result of executing the following application? (Choose all that apply.) 

import java.util.concurrent.*; 
import java.util.stream.*; 
public class Main { 
   public static void main(String[] args) { 
      ExecutorService service = Executors.newScheduledThreadPool(10); 
      DoubleStream.of(3.14159,2.71828) // b1 
         .forEach(c -> service.submit( // b2 
            () -> System.out.println(10*c))); // b3 
      service.execute(() -> System.out.println("Printed")); // b4 
   } // w  ww.  j a  v  a  2s  .  co m
}
  • A. It compiles and outputs the two numbers, followed by Printed.
  • B. The code will not compile because of line b1.
  • C. The code will not compile because of line b2.
  • D. The code will not compile because of line b3.
  • E. The code will not compile because of line b4.
  • F. It compiles but the output cannot be determined ahead of time.
  • G. It compiles but throws an exception at runtime.
  • H. It compiles but waits forever at runtime.


F, H.

Note

The application compiles and does not throw an exception, so B, C, D, E, and G are incorrect.

Even though the stream is processed in sequential order, the tasks are submitted to a thread executor, which may complete the tasks in any order.

Therefore, the output cannot be determined ahead of time and F is correct, making A incorrect.

Finally, the thread executor is never shut down; therefore the code will run but it will never terminate, making H also correct.




PreviousNext

Related