SCJP Threads

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SCJP mock Test

QUESTION : 1


   Any class that implements the Runnable interface
   has to provide the implementation for the following methods 
    public void start();
    public void run();

1. True.
2. False.

ANS : 2



QUESTION : 2
   
     True or false ?      

       A thread that has called the wait() method of an  object 
    still owns the lock of the object.
  


1. True
2. False

ANS : 2



QUESTION : 3
    
      A number of threads of the same priority  have relinquished the lock 
    on a monitor and are in a waiting state after having called the wait()
    method of the object. A new thread enters the monitor and calls the 
    notifyAll() method of the meonitor. Which of these threads will be the
    first one to resume? 
           

1. The thread that has been waiting the longest.
2. The thread that was the last one to to exit the monitor.
3. You can never be sure which thread will get to run first.
4. The the first thread that called the wait() method

ANS : 3


QUESTION : 4



     Which of these are valid contructors of a Thread object.

1. public Thread(Object obj) 
2. public Thread(String name)
2. public Thread(Runnable trgt)
4. public Thread(ThreadGroup grp, Runnable trgt, String name)
5. public Thread(ThreadGroup grp, Object ob)

ANS : 2,3,4



QUESTION : 5
 
    If you call  the interrupted() method of a thread object twice
    the second call will always return false.  


1. True
2. False

ANS : 1


QUESTION : 6


         If you call  the isInterrupted() method of a thread object twice
         the second call will always return false. 

1. True
2. False

ANS : 2


QUESTION : 7


      Which of the following are methods of the Thread class.


1. public void run()
2. public void start()
3. public void exit()
4. public final void setAccess()
5. public final void setPriority(int priNbr) 
6. public final int getPriority() 

ANS : 1,2,5,6


QUESTION : 8


   Consider the following class
      public class Test implements Runnable{
      public void run(){}
      }
   True or False ?
   Creating an instance of this class and calling its run() method 
   will spawn a new thread.   

1. True
2. False

ANS : 2


QUESTION : 9
     
       True or false?
       A Thread object has a method called notify().


1. False
2. True

ANS : 2

  The Thread class has a method notify() inherited from Object.  


QUESTION : 10


  Calling the destroy() method of a thread object relases all the locks held by
    the thread ?

1. True
2. False 

ANS : 2

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