Java Implementation of Problem 8

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public class p0008 implements IEuler
Object answer()
Returns:

The answer to Project Euler problem 8

 1/*
 2Project Euler Problem 8
 3
 4In Python I did this with an iterator, but that is more cumbersome here,
 5so I just did it with a loop that slices.
 6
 7Problem:
 8
 9The four adjacent digits in the 1000-digit number that have the greatest
10product are 9 × 9 × 8 × 9 = 5832.
11
1273167176531330624919225119674426574742355349194934
1396983520312774506326239578318016984801869478851843
1485861560789112949495459501737958331952853208805511
1512540698747158523863050715693290963295227443043557
1666896648950445244523161731856403098711121722383113
1762229893423380308135336276614282806444486645238749
1830358907296290491560440772390713810515859307960866
1970172427121883998797908792274921901699720888093776
2065727333001053367881220235421809751254540594752243
2152584907711670556013604839586446706324415722155397
2253697817977846174064955149290862569321978468622482
2383972241375657056057490261407972968652414535100474
2482166370484403199890008895243450658541227588666881
2516427171479924442928230863465674813919123162824586
2617866458359124566529476545682848912883142607690042
2724219022671055626321111109370544217506941658960408
2807198403850962455444362981230987879927244284909188
2984580156166097919133875499200524063689912560717606
3005886116467109405077541002256983155200055935729725
3171636269561882670428252483600823257530420752963450
32
33Find the thirteen adjacent digits in the 1000-digit number that have the
34greatest product. What is the value of this product?
35*/
36package euler;
37
38public class p0008 implements IEuler {
39    @Override
40    public Object answer() {
41        String str = ("73167176531330624919225119674426574742355349194934"
42                + "96983520312774506326239578318016984801869478851843"
43                + "85861560789112949495459501737958331952853208805511"
44                + "12540698747158523863050715693290963295227443043557"
45                + "66896648950445244523161731856403098711121722383113"
46                + "62229893423380308135336276614282806444486645238749"
47                + "30358907296290491560440772390713810515859307960866"
48                + "70172427121883998797908792274921901699720888093776"
49                + "65727333001053367881220235421809751254540594752243"
50                + "52584907711670556013604839586446706324415722155397"
51                + "53697817977846174064955149290862569321978468622482"
52                + "83972241375657056057490261407972968652414535100474"
53                + "82166370484403199890008895243450658541227588666881"
54                + "16427171479924442928230863465674813919123162824586"
55                + "17866458359124566529476545682848912883142607690042"
56                + "24219022671055626321111109370544217506941658960408"
57                + "07198403850962455444362981230987879927244284909188"
58                + "84580156166097919133875499200524063689912560717606"
59                + "05886116467109405077541002256983155200055935729725"
60                + "71636269561882670428252483600823257530420752963450");
61        long answer = 0;
62        for (int i = 0; i < str.length() - 13; i++) {
63            String slice = str.substring(i, i + 13);
64            long prod = 1;
65            for (int j = 0; j < slice.length(); j++)
66                prod *= slice.charAt(j) - '0';
67
68            if (prod > answer)
69                answer = prod;
70        }
71        return answer;
72    }
73}