How to find maximum value from a Integer using stream in Java 8?

Solution 1:

You may either convert the stream to IntStream:

OptionalInt max = list.stream().mapToInt(Integer::intValue).max();

Or specify the natural order comparator:

Optional<Integer> max = list.stream().max(Comparator.naturalOrder());

Or use reduce operation:

Optional<Integer> max = list.stream().reduce(Integer::max);

Or use collector:

Optional<Integer> max = list.stream().collect(Collectors.maxBy(Comparator.naturalOrder()));

Or use IntSummaryStatistics:

int max = list.stream().collect(Collectors.summarizingInt(Integer::intValue)).getMax();

int max = list.stream().reduce(Integer.MIN_VALUE, (a, b) -> Integer.max(a, b));

Another version could be:

int maxUsingCollectorsReduce = list.stream().collect(Collectors.reducing(Integer::max)).get();