Working with Streams and Lambda Expressions →mediumMultiple ChoiceObjective-mapped

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

Exhibit

List<Integer> numbers = Arrays.asList(1,2,3,4,5);
long count = numbers.stream().filter(n -> n%2==0).count();
System.out.println("Count: " + count);

Refer to the exhibit. What is the output?

⚠ Common exam trap

The trap here is that candidates often forget to account for the filter predicate or misread the list contents, leading them to count all elements or assume a different number of non-'A' elements without carefully tracing the stream operations.

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

✓

Count: 2

The stream filters out all elements equal to "A", leaving only elements that are not "A". Based on the list in the exhibit, there are exactly two such elements (e.g., "B" and "C"), so the count is 2.

Answer analysis

Option-by-option breakdown

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

✓
Count: 2
Why this is correct
Correct. The filter removes all elements equal to 'A', leaving only non-'A' elements. The exhibit shows exactly two such elements, so the count is 2.
✗
Count: 3
Why it's wrong here
Incorrect. A count of 3 would result if there were three non-'A' elements, but the list contains only two.
✗
Count: 1
Why it's wrong here
Incorrect. A count of 1 would result if there were only one non-'A' element, but the list contains two.
✗
Count: 4
Why it's wrong here
Incorrect. A count of 4 would result if the filter were not applied or if the list had four non-'A' elements. The actual list has fewer.

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