Greatest product of five consecutive digits in a 1000-digit number

Question

I am working through the problems on project Euler and am not too certain if my understanding of the question is correct.

Problem 8 is as follows:

Answer 1

public class Problem008
{
    public static int checkInt(String s)
    {
        int product = 1;
        for (int i = 0; i < 5; i++)
        {
            Character c = new Character(s.charAt(i));
            String tmp = c.toString();
            int temp = Integer.parseInt(tmp);
            product *= temp;
        }
        return product;
    }

    public static void main(String[] args)
    {
        long begin = System.currentTimeMillis();
        String BigNum = "7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450";
        String snip;
        int largest = 0;

        for (int i = 0; i <= (BigNum.length()-5); i++)
        {
            snip = null;

            for (int j = 0; j < 5; j++)
            {
                char c = BigNum.charAt(i+j);
                snip += c;
            }
            if (checkInt(snip) > largest)
                largest = checkInt(snip);
            }
            long end = System.currentTimeMillis();
            System.out.println(largest);
            System.out.println(end-begin + "ms");
        }
    }
}