Really confused by java data type in this specific case [duplicate]

Question

public class Test {
        public static void main(String [] s) {
            int x = 99999;
            long y = 99999;

            long res = x * x;
            System.out.println("x^2 = " + res);
            res = y * y;
            System.out.println("y^2 = " + res);
        }
    }



 Output: 
    x^2 = 1409865409
    y^2 = 9999800001

I am really confused to see the output from the above code segment. I expected to get the same (correct) answer but here x^2 is actually wrong!

Answer 1

99999 * 99999 = 1001010100000010001101011011000001 in binary (if you count these you will find out that you need 34 bits to represent this number in memory).

int is 32-bit long so two MSBs are cut out.

That gives you 01010100000010001101011011000001b = 1409865409 decimal as a result.

Assigning this value to 64-bit long doesn't change the result, multiplication of two integers gives you integer as a result.