2pts The following piece of code is intended to protect z ag

[2pts] The following piece of code is intended to protect z against integer overflow.

Put this piece of code into a java program and test it.

a.) [1pt] When you run it with values x=250100 and y=340200, what do you see as

output?

b.) [1pt] Find out what can be done to provide such protection in Java 8.

static boolean multiply (int x, int y) int z System. out println (\"x x and y y) if (x y> Integer .MIN VALUE && x y

Solution

a) The code when tested in java prints the wrong value of x*y for the values x=250100 and y=340200 as due to small size allocated to int, it wraps to the small nearest value

b) Java 8 provides this new feature of integer overflow protection

java.lang.math package in java 8 provides new methods such as addExact() and multiplyExact() which would give either the exact values of the operation if within the range or would throw an ArithmeticException.

I am giving an example for better understanding:

public class OverflowTest

{

    public static void main(String[] args)

    {

        int a = Integer.MAX_VALUE;

        int b = Integer.MAX_VALUE;

        try

        {

            int c = Math.addExact(a, b);

            System.out.println(a + \" + \" + b + \" = \" + c);

        }

        catch (ArithmeticException ex)

        {

            System.err.println(\"int is too small, falling back to long.\");

            long c = (long) a + (long) b;

            System.out.println(a + \" + \" + b + \" = \" + c);

        }

    }

}

This is the console:

$ javac OverflowTest.java
$ java OverflowTest
int is too small, falling back to long.
2147483647 + 2147483647 = 4294967294