Working with Streams and Lambda Expressions →mediumMultiple ChoiceObjective-mapped

1Z0-829 Working with Streams and Lambda Expressions Practice Question

Exhibit

Refer to the exhibit.
```java
List<Integer> numbers = Arrays.asList(2, 3, 4, 5);
int result = numbers.stream()
    .filter(n -> n % 2 == 0)
    .mapToInt(n -> n * 3)
    .sum();
System.out.println(result);
```

What is the output of the code above?

⚠ Common exam trap

Oracle often tests the interaction between `flatMap`, `filter`, and `limit` or `skip`, where candidates forget that `limit` truncates the stream after the filter, leading to an incorrect sum based on the first few elements rather than all matching elements.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

The code creates a stream of lists containing numbers 1 through 9, flatMaps to a single stream of integers, filters for numbers divisible by 3 (leaving 3, 6, 9), and reduces them by summing. The sum is 3+6+9=18, making option A correct.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✓
18
Why this is correct
Correct: (2*3)+(4*3)=6+12=18.
✗
15
Why it's wrong here
Incorrect: Might have forgotten filter.
✗
9
Why it's wrong here
Incorrect: That would be sum of 2+3+4? No.
✗
27
Why it's wrong here
Incorrect: If all numbers were processed: (2+3+4+5)*3=42? No.

Go deeper

1Z0-829 Working with Streams and Lambda Expressions Practice Question

Exhibit

Why each option matters

Option-by-option breakdown

Related to this question