I think the actual puzzle is fixing the code :)

public static List<Integer> serviceLane(int n, List<Integer> widths, List<List<Integer>> cases) {
    List<Integer> result = new LinkedList<>();
    for(List<Integer> _case:cases) {
        int start = _case.get(0);
        int end = _case.get(_case.size()-1);

        int min = widths.subList(start, end+1).stream().min(Integer::compare).get();
        result.add(min);
    }
    return result;
}