Enthuware

In need of help on the following question ?
Given:
List<Integer> primes = Arrays.asList(2, 3, 5, 7, 11, 13, 17); //1
Stream<Integer> primeStream = primes.stream(); //2

Predicate<Integer> test1 = k->k<10; //3

the given answer on the enthuware mockExam says the correct answer is as follows .

primeStream.collect(Collectors.partitioningBy(test1,Collectors.counting())).values().forEach(System.out::print)

can you make a method call like values() on a terminal operator like the callect() method ? does it even compile ?

What happened when you tried to compile/run it?
values() returns a new Stream and you can certainly process the elements of that stream using forEach.

why are the values switched in the last (correct) option? from 4 then 3, to 3 then 4.

Since you are passing Collectors.partitioningBy to primeStream.collect, the result is actually a map containing key value pairs (true,4) and (false, 3). Now, when you call values().forEach on this map, the order of the values returned is implementation dependent (i.e. depends on the implementation of the map generated by the collect method). In this case, it returns 3, 4 but some other implementation may return 4, 3.