Java SE 8 Programmer II — Question 196

Which two methods from the java.util.stream.Stream interface perform a reduction operation? (Choose two.)

Answer options

• A. count ()
• B. collect ()
• C. distinct ()
• D. peek ()
• E. filter ()

Correct answer: A, B

Explanation

The correct answers are A and B because both count() and collect() perform reduction operations; count() aggregates elements into a single count, while collect() gathers elements into a collection. The other options, distinct(), peek(), and filter(), do not perform reductions but instead transform or filter the stream without aggregating results.