api - Difference between stream.max(Comparator) and stream.collect(Collectors.maxBy(Comparator) in Java

Question

In Java Streams - what is the difference between stream.max(Comparator) and stream.collect(Collectors.maxBy(Comparator)) in terms of preformance. Both will fetch the max based on the comparator being passed. If this is the case why do we need the additional step of collecting using the collect method? When should we choose former vs latter? What are the use case scenarios suited for using both?

Answer 1

They do the same thing, and share the same code.

why do we need the additional step of collecting using the collect method?

You don't. Use max() if that's what you want to do. But there are cases where a Collector can be handy. For example:

Optional<Foo> result = stream.collect(createCollector());

where createCollector() would return a collector based on some condition, which could be maxBy, minBy, or something else.

In general, you shouldn't care too much about the small performance differences that might exist between two methods that do the same thing, and have a huge chance of being implemented the same way. Instead, you should make your code as clear and readable as possible.