1Z0-829 Working with Arrays and Collections Practice Question
Which THREE statements are true about the java.util.Collection and java.util.stream.Stream APIs? (Choose three.)
⚠ Common exam trap
It's easy for candidates to assume forEach() always preserves order regardless of stream type, but the Stream API explicitly states that forEach() does not guarantee encounter order for parallel streams, unlike forEachOrdered().
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 Stream.forEach() operation processes elements in the encounter order of the stream only for sequential streams.
The Stream.forEach() operation respects the encounter order of the stream only for sequential streams. For parallel streams, the order is not guaranteed unless the stream is explicitly forced to be sequential or uses forEachOrdered(). This behavior is defined in the Stream API specification.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The Collection.forEach() method is inherited from the Collection interface.
Why it's wrong here
It is inherited from Iterable.
- ✓
The Stream.forEach() operation processes elements in the encounter order of the stream only for sequential streams.
Why this is correct
Parallel streams may process elements out of order.
- ✗
The Collection interface inherits the stream() method from the Iterable interface.
Why it's wrong here
stream() is defined in Collection, not Iterable.
- ✓
The Stream.toList() method returns an unmodifiable list.
Why this is correct
Since Java 16.
- ✓
The Iterator interface provides a default method forEachRemaining(Consumer<? super E> action).
Why this is correct
Introduced in Java 8.
Go deeper
Related to this question
About these practice questions
One of 513 original 1Z0-829 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.