As of Java-9, there exists [IntStream.html#iterate(seed, hasNext, next)](https://docs.oracle.com/javase/10/docs/api/java/util/stream/IntStream.html#iterate(int,java.util.function.IntPredicate,java.util.function.IntUnaryOperator))

If you are trying to get a comma separated list of speeds, use:

    String allSpeeds = IntStream.iterate(minKmh, i -> i <= maxKmh, i -> i + step)
                                .mapToObj(Integer::toString)
                                .collect( Collectors.joining( "," ) );

If you just want the integer array of speeds:

    int[] speeds = IntStream.iterate(minKmh, i -> i <= maxKmh, i -> i + step).toArray();

Or, if you want the array of speeds as Strings:

    String[] allSpeedsAsArray = IntStream.iterate(minKmh, i -> i <= maxKmh, i -> i + step)
                                         .mapToObj(Integer::toString)
                                         .toArray();