The correct answer is that Duration can be negative. This is because the java.time.Duration class models a time-based amount of time in seconds and nanoseconds, representing quantities like hours, minutes, and seconds, and unlike Period, it is not tied to calendar dates—so a negative duration simply indicates a time interval going backward. On the Oracle Certified Professional Java SE 17 Developer 1Z0-829 exam, this concept tests your understanding of the Duration class overview and its properties, often appearing in questions that try to confuse Duration with Period or with the assumption that time amounts must always be positive. A common trap is thinking Duration only stores positive values, but the API explicitly allows negative values to represent elapsed time in reverse. Memory tip: think of a stopwatch that can count down as well as up—Duration handles both directions.
1Z0-829 Practice Question: Handling Date, Time, Text, Numeric and Boolean Values
This 1Z0-829 practice question tests your understanding of handling date, time, text, numeric and boolean values. 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.
Which TWO statements are true about the java.time.Duration class? (Choose two.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Duration represents a time-based amount of time, such as hours, minutes, seconds.
Option A is correct because the java.time.Duration class models a time-based amount of time in terms of seconds and nanoseconds, which can represent hours, minutes, seconds, and smaller units. It is designed for time-based quantities, not date-based ones like days, months, or years.
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.
✓
Duration represents a time-based amount of time, such as hours, minutes, seconds.
Why this is correct
Duration is based on seconds/nanoseconds.
Related concept
Read the scenario before looking for a memorised answer.
✗
Duration.ofDays(1) returns a Duration that is daylight-saving-safe.
Why it's wrong here
Duration is fixed 24 hours, not DST-aware.
✗
Duration.between(LocalDate.now(), LocalDate.now().plusDays(1)) returns a Duration of 1 day.
Why it's wrong here
Duration.between requires temporals that support seconds; LocalDate does not.
✗
Duration can represent a period of months.
Why it's wrong here
Period represents months, not Duration.
✓
Duration can be negative.
Why this is correct
Duration can be negative.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse Duration with Period, mistakenly thinking Duration can handle days, months, or daylight-saving adjustments, or that Duration.between() works with any temporal type like LocalDate.
Detailed technical explanation
How to think about this question
Under the hood, Duration stores a long for seconds and an int for nanoseconds, allowing it to represent precise time spans. A key subtlety is that Duration.between() throws DateTimeException if the temporal objects do not support the SECONDS field, which is why LocalDate fails. In real-world scenarios, using Duration for time-based calculations (e.g., measuring elapsed time) is safe, but for date-based intervals (e.g., adding 1 month), Period must be used to handle variable month lengths.
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.
Handling Date, Time, Text, Numeric and Boolean Values — This question tests Handling Date, Time, Text, Numeric and Boolean Values — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Duration represents a time-based amount of time, such as hours, minutes, seconds. — Option A is correct because the java.time.Duration class models a time-based amount of time in terms of seconds and nanoseconds, which can represent hours, minutes, seconds, and smaller units. It is designed for time-based quantities, not date-based ones like days, months, or years.
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 →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which two statements about the java.time.Duration class are true? (Choose two.)
medium
A.Duration supports units like months and years.
✓ B.Duration can be negative.
✓ C.Duration is immutable and thread-safe.
D.Duration.between(LocalDate.now(), LocalDate.now()) returns a Duration.
E.Duration uses a days-based representation.
Why B: Option B is correct because the java.time.Duration class can represent negative durations, such as when the end instant is before the start instant in a Duration.between() call. Option C is correct because all classes in the java.time package, including Duration, are immutable and thread-safe by design, ensuring safe concurrent access without synchronization.
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Question Discussion
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