Quick Answer
The answer is Count: 2. This is correct because the stream pipeline first applies a filter to retain only even numbers from the list, then calls count() as a terminal operation, which returns the number of elements that passed through the filter—in this case, 2 and 4. The key technical concept here is that stream operations are lazy until a terminal operation like count() is invoked, and the filter predicate must be a stateless, non-interfering function. On the Oracle Certified Professional Java SE 17 Developer 1Z0-829 exam, this pattern tests your understanding of intermediate versus terminal operations, and a common trap is forgetting that count() returns a long, not an int, or mistakenly counting all elements before the filter. To avoid errors, always trace the pipeline step by step: identify what the filter keeps, then apply the terminal operation. A helpful memory tip is “filter first, then count—the filter decides what makes the cut.”
This 1Z0-829 practice question tests your understanding of working with streams and lambda expressions. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
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?
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);Count: 2
A is correct: there are two even numbers (2 and 4).
Count: 3
Why wrong: B is wrong: there are not three evens.
Count: 1
Why wrong: D is wrong: only one even? No, there are two.
Count: 4
Why wrong: C is wrong: incorrect count.
Answer choices
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 correct output is 'Count: 2' because the stream filters even numbers (2,4) and counts them, resulting in 2.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Count: 2
Why this is correct
A is correct: there are two even numbers (2 and 4).
Related concept
Read the scenario before looking for a memorised answer.
Count: 3
Why it's wrong here
B is wrong: there are not three evens.
Count: 1
Why it's wrong here
D is wrong: only one even? No, there are two.
Count: 4
Why it's wrong here
C is wrong: incorrect count.
Common exam traps
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the 1Z0-829 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Identify which 1Z0-829 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Working with Streams and Lambda Expressions — study guide chapter
Learn the concepts, then practise the questions
Working with Streams and Lambda Expressions practice questions
Targeted practice on this topic area only
All 1Z0-829 questions
509 questions across all exam domains
Oracle Certified Professional Java SE 17 Developer 1Z0-829 study guide
Full concept coverage aligned to exam objectives
1Z0-829 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise 1Z0-829 questions linked to Handling Date, Time, Text, Numeric and Boolean Values.
Practise 1Z0-829 questions linked to Controlling Program Flow.
Practise 1Z0-829 questions linked to Utilizing Java Object-Oriented Approach.
Practise 1Z0-829 questions linked to Handling Exceptions.
Practise 1Z0-829 questions linked to Working with Arrays and Collections.
Practise 1Z0-829 questions linked to Working with Streams and Lambda Expressions.
Practise 1Z0-829 questions linked to Java Platform Overview and Packaging.
Practise 1Z0-829 questions linked to Java I/O API and Securing Applications.
Practise 1Z0-829 questions linked to 1Z0-829 fundamentals.
Practise 1Z0-829 questions linked to 1Z0-829 scenario.
Practise 1Z0-829 questions linked to 1Z0-829 troubleshooting.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Working with Streams and Lambda Expressions — This question tests Working with Streams and Lambda Expressions — Read the scenario before looking for a memorised answer..
The correct answer is: Count: 2 — The correct output is 'Count: 2' because the stream filters even numbers (2,4) and counts them, resulting in 2.
Identify which 1Z0-829 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Keep practising
Last reviewed: Jun 24, 2026
This 1Z0-829 practice question is part of Courseiva's free Oracle certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 1Z0-829 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.