Java 8 find max [duplicate]

Answer 1

You need to invoke map on intStream

System.out.println(list.stream().mapToInt(Integer::intValue).max().getAsInt());

Currently your code just returns the first value from the list i.e. 4 in your case

Answer 2

Stream#max(Comparator) takes a Comparator. You'll want to use Integer#compare(int, int) as that comparison function.

list.stream().max(Integer::compare).get()

You were providing Integer#max(int, int) as an implementation of Comparator#compare(int, int). That method doesn't match the requirements of Comparator#compare. Instead of returning a value indicating which is biggest, it returns the value of the biggest.