Produce combinations of dice

CombinationsOfDice.java

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class CombinationsOfDice {
  public List<int[]> execute(final int numberOfDice, final int numberOfSidesPerDice) {
    final List<int[]> list = new ArrayList<>();

    final int[] combination = new int[numberOfDice];
    int index;

    Arrays.fill(combination, 1);

    index = numberOfDice - 1;
    combination[index] = 0;

    while (true) {
      if (combination[index] == numberOfSidesPerDice) {
        index--;
        if (index < 0) break;
      } else {
        combination[index]++;
        while (index < numberOfDice - 1) {
          index++;
          combination[index] = 1;
        }
        list.add(Arrays.copyOf(combination, numberOfDice));
      }
    }

    return list;
  }
}