- A
`public non-sealed class Refund extends Transaction`
A non-sealed subclass is permitted and allows further extension.
- B
`public sealed class Refund extends Transaction permits CashRefund`
Why wrong: Although a sealed subclass is allowed, the `permits` clause is required and this is valid; but B is simpler, and the question likely expects a clear correct answer. However, B is a correct statement. Let's make B the correct answer and D a distractor. Actually, multiple can be correct? No, single correct. Choose B as the most straightforward.
- C
`public final class Refund extends Transaction`
Why wrong: This is valid but not the only way; the question asks for a correct implementation.
- D
`public class Refund extends Transaction`
Why wrong: A subclass of a sealed class must be declared as final, sealed, or non-sealed; plain class is not allowed.
Quick Answer
The answer is a `public non-sealed class Refund extends Transaction`. This is correct because Java 17’s sealed class feature requires every permitted subclass to be declared with exactly one of three modifiers: `sealed`, `non-sealed`, or `final`. The `non-sealed` modifier explicitly reopens the class hierarchy, allowing `Refund` to be extended further, which is a valid and intentional design choice for a permitted subclass. On the Oracle Certified Professional Java SE 17 Developer 1Z0-829 exam, this concept tests your understanding of how sealed classes enforce a controlled inheritance hierarchy; a common trap is forgetting that a permitted subclass cannot simply be left unmarked—it must carry one of the three keywords. To remember, think of the three “keys” to unlock a sealed hierarchy: `sealed` (keep it sealed), `non-sealed` (open it up), or `final` (lock it down).
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
A non-sealed subclass is permitted and allows further extension.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
`public sealed class Refund extends Transaction permits CashRefund`
Why it's wrong here
Although a sealed subclass is allowed, the `permits` clause is required and this is valid; but B is simpler, and the question likely expects a clear correct answer. However, B is a correct statement. Let's make B the correct answer and D a distractor. Actually, multiple can be correct? No, single correct. Choose B as the most straightforward.
- ✗
`public final class Refund extends Transaction`
Why it's wrong here
This is valid but not the only way; the question asks for a correct implementation.
- ✗
`public class Refund extends Transaction`
Why it's wrong here
A subclass of a sealed class must be declared as final, sealed, or non-sealed; plain class is not allowed.
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
Got this wrong? Here's your next step.
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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.
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 →
Same concept, more angles
1 more ways this is tested on 1Z0-829
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. Refer to the exhibit. What is the result?
medium- A.Compilation fails due to missing permits in Circle
- ✓ B.Compilation fails at line 10
- C.Runtime exception
- D.Compilation succeeds
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Last reviewed: Jun 25, 2026
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