The correct approach is to use Boolean.FALSE.equals(flag) within a ternary assignment, as in flag = Boolean.FALSE.equals(flag) ? Boolean.FALSE : flag. This works because the equals method on Boolean.FALSE is called on a known non-null object, so it safely handles a null flag reference without throwing a NullPointerException; if flag is null, equals returns false, causing the ternary to assign Boolean.FALSE, while if flag is already Boolean.FALSE it stays unchanged, and otherwise it retains the original value. On the Oracle Certified Professional Java SE 17 Developer 1Z0-829 exam, this pattern tests your understanding of null-safe assignment with Boolean wrappers, a common trap where candidates mistakenly use flag == null or flag.equals(Boolean.FALSE) which would throw an exception. Remember the mnemonic: “Call equals on the constant, not the variable” to keep null safety invariable.
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.
A method receives a Boolean reference and must set it to false if null. Which code accomplishes this correctly?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
flag = Boolean.FALSE.equals(flag) ? Boolean.FALSE : flag;
Option B is correct because it uses Boolean.FALSE.equals(flag) which safely handles a null flag reference without throwing a NullPointerException. If flag is null, equals returns false, so the ternary assigns Boolean.FALSE; if flag is already Boolean.FALSE, it stays unchanged; otherwise, it keeps the original value. This matches the requirement to set the Boolean reference to false only when it is null.
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.
✗
if (flag = null) flag = Boolean.FALSE;
Why it's wrong here
Assignment instead of comparison; also unboxing null throws NPE.
✓
flag = Boolean.FALSE.equals(flag) ? Boolean.FALSE : flag;
Why this is correct
Uses equals() safely; if flag is null, equals returns false, so ternary sets to false.
Related concept
Read the scenario before looking for a memorised answer.
✗
if (flag == null) flag = false;
Why it's wrong here
Autounboxing null to boolean throws NullPointerException.
✗
if (flag.equals(Boolean.FALSE)) flag = null;
Why it's wrong here
Throws NullPointerException if flag is null; logic reversed.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often pick Option C because they think a simple null check with == and assignment of false works, but they overlook that the assignment of primitive false to a Boolean reference is allowed via autoboxing, yet the exam expects the use of the Boolean wrapper's equals method as the correct and safe approach for Boolean objects.
Detailed technical explanation
How to think about this question
The Boolean.FALSE.equals(flag) method is safe because the equals method of Boolean handles null gracefully by returning false when the argument is null, as per the Java Language Specification. This pattern is commonly used to avoid explicit null checks when dealing with Boolean wrapper objects, especially in legacy code or when working with APIs that return Boolean objects. In real-world scenarios, such as parsing configuration values or database results, Boolean references can be null, and using equals ensures null-safe comparison without additional if statements.
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: flag = Boolean.FALSE.equals(flag) ? Boolean.FALSE : flag; — Option B is correct because it uses Boolean.FALSE.equals(flag) which safely handles a null flag reference without throwing a NullPointerException. If flag is null, equals returns false, so the ternary assigns Boolean.FALSE; if flag is already Boolean.FALSE, it stays unchanged; otherwise, it keeps the original value. This matches the requirement to set the Boolean reference to false only when it is null.
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.
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Question Discussion
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