This inspection reports stream API call chains which can be simplified. It allows to avoid creating redundant temporary objects when traversing a collection.

The following call chains are replaced by this inspection:

collection.stream().forEach() → collection.forEach()
collection.stream().collect(toList/toSet/toCollection()) → new CollectionType<>(collection)
collection.stream().toArray() → collection.toArray()
Arrays.asList().stream() → Arrays.stream() or Stream.of()
IntStream.range(0, array.length).mapToObj(idx -> array[idx]) → Arrays.stream(array)
IntStream.range(0, list.size()).mapToObj(idx -> list.get(idx)) → list.stream()
Collections.singleton().stream() → Stream.of()
Collections.emptyList().stream() → Stream.empty()
stream.filter().findFirst().isPresent() → stream.anyMatch()
stream.collect(counting()) → stream.count()
stream.collect(maxBy()) → stream.max()
stream.collect(mapping()) → stream.map().collect()
stream.collect(reducing()) → stream.reduce()
stream.collect(summingInt()) → stream.mapToInt().sum()
stream.mapToObj(x -> x) → stream.boxed()
stream.map(x -> {...; return x;}) → stream.peek(x -> ...)
!stream.anyMatch() → stream.noneMatch()
!stream.anyMatch(x -> !(...)) → stream.allMatch()
stream.map().anyMatch(Boolean::booleanValue) -> stream.anyMatch()

Note that the replacements semantic may have minor difference in some cases. For example, Collections.synchronizedList(...).stream().forEach() is not synchronized while Collections.synchronizedList(...).forEach() is synchronized. Or collect(Collectors.maxBy()) would return an empty Optional if the resulting element is null while Stream.max() will throw NullPointerException in this case.