Questions and answers for exam Preparation

MCQs

Total Questions : 22 | Page 2 of 3 pages

Question 11. Predict the output:class A implements Runnable{ public void run(){ try{ for(int i=0;i

A B A B A B A B
Compilation succeed but Runtime Exception
A A A A B B B B
Output order is not guaranteed
None of these

Discuss Question

Answer: Option C. -> A A A A B B B B

Question 12. What notifyAll() method do?

None of these
Wakes up one threads that are waiting on this object's monitor
Wakes up all threads that are waiting on this object's monitor
Wakes up all threads that are not waiting on this object's monitor

Discuss Question

Answer: Option C. -> Wakes up all threads that are waiting on this object's monitor

Question 13. Which of the following are methods of the Thread class?1) yield()2) sleep(long msec)3) go()4) stop()

3 only
None of these
1 , 2 and 4
1 and 3

Discuss Question

Answer: Option C. -> 1 , 2 and 4

Question 14. What will happen when you attempt to compile and run the following code?class A implements Runnable{ public void run(){ System.out.println("run-A"); }}1. public class Test{2. public static void main(String argv[]){3. A a = new A();4. Thread t = new Thread(a);5. System.out.println(t.isAlive());6. t.start();7. System.out.println(t.isAlive());8. }9. }

None of these
false run-A false
true run-A true
false run-A true
Compilation fails due to an error on line 7

Discuss Question

Answer: Option D. -> false run-A true

Question 15. What will be the output?class A extends Thread{ public void run(){ for(int i=0; i

0 0
Compilation succeed but runtime exception
0 1
Compilation error, class A has no start method
None of these

Discuss Question

Answer: Option C. -> 0 1

Question 16. What is the output for the below code ?public class Test extends Thread{ public static void main(String argv[]){ Test t = new Test(); t.run(); } public void start(){ for(int i = 0; i < 10; i++){ System.out.println("Value of i = " + i); } }}

None of these
A run time error indicating that no run method is defined for the Thread class
Clean compile but no output at runtime
A compile time error indicating that no run method is defined for the Thread class
Clean compile and at run time the values 0 to 9 are printed out

Discuss Question

Answer: Option C. -> Clean compile but no output at runtime

Question 17. Which keyword when applied on a method indicates that only one thread should execute the method at a time.

native
volatile
static
synchronized
final

Discuss Question

Answer: Option D. -> synchronized

Question 18. Predict the output:public class Test extends Thread{ private int i; public void run(){ i++; } public static void main(String[] args){ Test a = new Test(); a.run(); System.out.print(a.i); a.start(); System.out.print(a.i); }}

IllegalThreadStateException is thrown
Prints
Prints
Compiler error
Prints

Discuss Question

Answer: Option E. -> Prints

Question 19. What will be the output after compiling and executing the following code?public class Test implements Runnable{ public static void main(String[] args) throws InterruptedException{ Thread a = new Thread(new Test()); a.start(); System.out.print("Begin"); a.join(); System.out.print("End"); } public void run(){ System.out.print("Run"); }}

"BeginEndRun" is printed.
"BeginEnd" is printed.
Compilation fails.
An exception is thrown at runtime.
"BeginRunEnd" is printed.

Discuss Question

Answer: Option E. -> "BeginRunEnd" is printed.

Question 20. What is the output for the below code ?class A implements Runnable{ public void run(){ System.out.println(Thread.currentThread().getName()); }}1. public class Test{2. public static void main(String... args){3. A a = new A();4. Thread t = new Thread(a);5. t.setName("good");6. t.start();7. }8. }