the output  is
y is 6
a is 9
x is 6
is correct .
u got a method  call before printing the value of x,so first it goes into the
method calla nd perform the necessary operation,in the method foo(int,int) u got
two println  statements for y and a so first it prints them first and then it
prints the value of x,hope u got.

That is true

Because the first function is main, right?

But in your main  function you called other function foo(x,y)

And in your foo function you have print the result for y and a

So x is shown the last



Check it again and you will find out.

You infact call the second method  before the main  method ends.

So you are right the main method fires first, but if you call something
else from the main method it will run the called bits from the main method.

<main()>
int z = foo(x,y);

System.out.println("x is " + x);
</main()>

To find the value of Z, it must run the method foo(x,y). It can't go on
untill it has the answer for the variable z.

However if you where to do something like ...

public static  void main(String[] args) {

int x = 6;

int y = 3;

int z;

System.out.println("x is " + x);

z = foo(x, y);
}

Your out put would be right.

The reson for this is that you are finding the actual value for z after
you printout the results of x.