com_baeldung_algorithms_radixsort_RadixSortUnitTest_java
com.baeldung.algorithms.radixsort.RadixSort
private static int findMaximumNumberIn(int[] arr) {         return Arrays.stream(arr).max().getAsInt();

 -> java.util.Arrays.stream(int[]): java.util.stream.IntStream -> java.util.stream.IntStream.max(): java.util.OptionalInt -> java.util.OptionalInt.getAsInt(): int