Java OCA OCP Practice Question 2763

Question

Which of the following can we add after line 5 for the code to run without error and not produce any output? (Choose all that apply.) 

4:    LongStream ls = LongStream.of(1, 2, 3); 
5:    OptionalLong opt = ls.map(n -> n * 10).filter(n -> n < 5).findFirst(); 

A.   if (opt.isPresent()) System.out.println(opt.get());
B.   if (opt.isPresent()) System.out.println(opt.getAsLong());
C.   opt.ifPresent(System.out.println)
D.   opt.ifPresent(System.out::println)
E.   None of these; the code does not compile.
F.   None of these; line 5 throws an exception at runtime.



B, D.

Note

Option A would work for a regular Stream.

However, we have a LongStream and therefore need to call getAsLong().

Option C is missing the :: that would make it a method reference.

Therefore, options B and D are correct.




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