public class IncDec
      {
         public static void main (String [] args)
               {
                   Alpha alpha = new Alpha (5);
                   Incrementor i = new Incrementor (alpha);
                   Decrementor d = new Decrementor (alpha);
                   Thread t1 = new Thread (i);
                   Thread t2 = new Thread (d);
                   t1.start ();
                   t2.start ();
              }
      }

class Alpha
     {
         private int alpha;
         public Alpha (int beta)
               {
                   alpha = beta;
               }
         public void decrement ()
               {
                  -- this.alpha;
                  System.out.println (this);
               }
         public void increment ()
               {
                  ++ this.alpha ;
                  System.out.println (this);
               }
         public String toString ()
               {
                   return "Now alpha = " + alpha;
               }
      }

class Incrementor implements Runnable
     {
         private Alpha x;
         public Incrementor (Alpha y)
               {
                  x = y;
               }
         public void run ()
               {
                  for (int i = 0; i < 10; i ++)
                     {
                        x.increment ();
                     }
               }
     }

class Decrementor implements Runnable
     {
        private Alpha x;
        public Decrementor (Alpha y)
              {
                 x = y;
              }
        public void run ()
              {
                for (int i = 0; i < 10; i ++)
               {
                  x.decrement ();
               }
              }
      }

Q1) The output of this program can begin with 4 or 5 or 6.

Q2) The output of this program will always end with 5.

Q3) There is a scenario in which the output of
the program can begin with 5 5.

Q4) A ReentrantLock was declared as a field of the class
Alpha, and defined as a member of its created objects.
The code contained within the body of Alpha's methods
decrement () and increment () was enclosed within
a pair of lock () and unlock () method calls.
The output of the modified program cannot begin with 5.


The program was further modified by placing a
call to sleep (100) after the statement
x.increment () in the run () method of
Incrementor.

Q5) There is no scenario in which the output can begin
with 4.

Q6) There is no scenario in which the output can begin
with 5.

Q7) There is a scenario in which the output can begin
with 6.

Q8) There is a scenario in which the output can end
with 5.

Q9) There is not a scenario in which the output can end
with 4?

Q10) There is not a scenario in which the output can end
with 6?