- A
`public non-sealed class Refund extends Transaction`
Correct. The `non-sealed` modifier allows further subclassing, which is a valid implementation of a permitted subclass of a sealed class.
- B
`public sealed class Refund extends Transaction permits CashRefund`
Why wrong: Incorrect. Although a subclass can be declared as `sealed`, this option introduces an unnecessary `permits` clause for `CashRefund`, which is not defined and distracts from the core requirement.
- C
`public final class Refund extends Transaction`
Why wrong: Incorrect. A `final` subclass is valid for a sealed class, but the question expects the subclass to be extendable, so `non-sealed` is the intended correct modifier.
- D
`public class Refund extends Transaction`
Why wrong: Incorrect. A subclass of a sealed class must be declared with `sealed`, `non-sealed`, or `final`. Omitting the modifier causes a compilation error.
1Z0-829 Utilizing Java Object-Oriented Approach Practice Question
This 1Z0-829 practice question tests your understanding of utilizing java object-oriented approach. 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 class `Transaction` is declared as `sealed`. Which statement correctly implements a permitted subclass?
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
`public non-sealed class Refund extends Transaction`
Option A is correct because a sealed class requires its permitted subclasses to be explicitly declared with `sealed`, `non-sealed`, or `final`. The `non-sealed` modifier allows the subclass to be extended further, which is valid for a permitted subclass of a sealed class.
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.
- ✓
`public non-sealed class Refund extends Transaction`
Why this is correct
Correct. The `non-sealed` modifier allows further subclassing, which is a valid implementation of a permitted subclass of a sealed class.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
`public sealed class Refund extends Transaction permits CashRefund`
Why it's wrong here
Incorrect. Although a subclass can be declared as `sealed`, this option introduces an unnecessary `permits` clause for `CashRefund`, which is not defined and distracts from the core requirement.
- ✗
`public final class Refund extends Transaction`
Why it's wrong here
Incorrect. A `final` subclass is valid for a sealed class, but the question expects the subclass to be extendable, so `non-sealed` is the intended correct modifier.
- ✗
`public class Refund extends Transaction`
Why it's wrong here
Incorrect. A subclass of a sealed class must be declared with `sealed`, `non-sealed`, or `final`. Omitting the modifier causes a compilation error.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may think only `final` or `sealed` are valid for permitted subclasses, forgetting that `non-sealed` is also a valid modifier that explicitly reopens the hierarchy.
Detailed technical explanation
How to think about this question
Sealed classes in Java 17 (JEP 409) enforce a closed hierarchy by requiring all direct subclasses to be explicitly listed in the `permits` clause. The permitted subclasses must then be declared with one of three modifiers: `final` (no further subclasses), `sealed` (continues the sealed hierarchy), or `non-sealed` (opens the hierarchy to unknown subclasses). This design prevents unauthorized extensions while allowing controlled flexibility, such as in domain modeling where a base `Payment` class permits `CreditCard`, `DebitCard`, and `Cash` as subclasses, with `Cash` declared `non-sealed` to allow future subtypes.
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 security administrator must allow nursing staff to reach a patient records server while blocking access from the guest Wi-Fi VLAN. After applying an extended ACL, traffic is still blocked from nursing workstations. The ACL was applied outbound instead of inbound on the wrong interface. Questions like this test ACL direction and placement rules.
What to study next
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FAQ
Questions learners often ask
What does this 1Z0-829 question test?
Utilizing Java Object-Oriented Approach — This question tests Utilizing Java Object-Oriented Approach — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: `public non-sealed class Refund extends Transaction` — Option A is correct because a sealed class requires its permitted subclasses to be explicitly declared with `sealed`, `non-sealed`, or `final`. The `non-sealed` modifier allows the subclass to be extended further, which is valid for a permitted subclass of a sealed class.
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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Last reviewed: Jun 25, 2026
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