Threads doubt from mock

[Srikanth Iyer]

public class Abc{

private int x;

private int y;

public synchronized void setX (int i) (x=1

public synchronized void setY (int i) (y=1

public synchronized void setXY (int i) (setX(i) ; sety(i)

public synchronized Boolean check() { return x != y; }

}


A) check() can never return true.

B) check() can return true when setXY is called by multiple threads.

C) check() can return true when multiple threads call setX and setY separately.

D) check can only return true if Abc is changed to allow x and y to be set separately.


I think the check() method can never return true.

Please comment......................

Thank you in advance

[Lucky J Verma]

Can iget to know the annswer.
I also think ,Check() never returns true

[ahmed yehia]

IMP 'c' is more likely to be the only option.

[Sarikaa Bhatnagar]

Hi,

I feel choice D is correct and Abc can return false. Imagine a case when a thread has called setx() and sety() and setxy() are not called by any thread in that case value of x=1 and y=0( default intilization of member variables).
So if we remove the option of calling both the methods together then they will have diff values......

Please let us know the correct answer and the explantion also..........

Thanks,
Sarika.

[Sarikaa Bhatnagar]

Hi,

am sorry i think the sentence(Imagine a case when a thread has called setx() and sety() and setxy() are not called by any thread ) above is not very clear so reframing it.

Imagine a case when a thread has called setx() only and no other methods are called by any other thread(sety() and setxy() are not called by any thread ).

Thanks.

[Srikanth Iyer]

The answer is A)

but why not b)???

Please comment.............

Thank you in advacne

[Raef Kandeel]

Please quote your sources.