JDiscuss Test5 Question

[Vishnu Prakash]

  
public void run()
{
   synchronized(obj)
   {
     for(; :wink: 
     {
      x++; y++; System.out.println(x+" "+y);
     }
   }
}
 
public static void main(String[] args)
{
   new Test().start();
   new Test().start();
}
}
 

What will the above code print?

Options

Select 1 correct option.

1.It will keep on printin same values for x and y incrementing by 1 on each line.
2.It will keep on printin same values for x and y but they may be incrementing by more than 1 on each line.
3.It may print different values for x and y but both the values will be incrementing by 1 on each line.
4.You cannot say anything about the values.

The answer given is option 1. I think the answer is option 4.

Please give your suggestion

[Satish Chilukuri]

Option 1 is correct.

Both the incrementation and the printing operations are in the same synchronized block. As such it is like an atomic operation. If you increment, then you have to print.

At any given time since only one thread can increment x and y, and since you are incrementing in steps of one, the correct choice would be option 1 (assuming x and y were initialized with the same value)