Collectors.joining with Delimiter — String Concatenation
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.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
apple, banana, cherry
Option A is correct because the code uses `Collectors.joining(", ")` which concatenates the stream elements into a single string separated by ", ". The stream contains three elements: "apple", "banana", and "cherry". The joining collector does not add a trailing delimiter, so the output is exactly "apple, banana, cherry".
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
apple, banana, cherry
Why this is correct
Filter with length > 4 keeps 'apple' (5), 'banana' (6), 'cherry' (6). 'date' (4) is filtered out. Joined with ', '.
Related concept
Read the scenario before looking for a memorised answer.
✗
banana, cherry
Why it's wrong here
Omits 'apple' which has length 5 > 4.
✗
apple, banana, cherry,
Why it's wrong here
Trailing comma due to incorrect joining.
✗
apple, banana, cherry, date
Why it's wrong here
Includes 'date' which has length 4, not > 4.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may mistakenly think `joining(", ")` adds a trailing delimiter after the last element, similar to how some other languages handle string joins, or they may forget that the stream contains exactly the elements listed and not an extra "date".
Detailed technical explanation
How to think about this question
The `Collectors.joining(CharSequence delimiter)` internally uses a `StringBuilder` and appends the delimiter only between elements, not after the last one. This is implemented by tracking whether it is the first element and skipping the delimiter for the first element. In real-world scenarios, this collector is commonly used for generating CSV-like output or log messages where a clean, delimiter-separated list without trailing punctuation is required.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
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
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Working with Streams and Lambda Expressions — This question tests Working with Streams and Lambda Expressions — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: apple, banana, cherry — Option A is correct because the code uses `Collectors.joining(", ")` which concatenates the stream elements into a single string separated by ", ". The stream contains three elements: "apple", "banana", and "cherry". The joining collector does not add a trailing delimiter, so the output is exactly "apple, banana, cherry".
What should I do if I get this 1Z0-829 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
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 →
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.
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.