1Z0-829 Java I/O API and Securing Applications Practice Question
This 1Z0-829 practice question tests your understanding of java i/o api and securing applications. 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 company uses serialization to transfer objects between microservices. To prevent deserialization attacks, they want to restrict which classes can be deserialized. Which approach should be used in Java 17?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use ObjectInputFilter with a custom filter
Option C is correct because Java 17 provides the `ObjectInputFilter` API (introduced in Java 9) as the standard mechanism to restrict which classes can be deserialized. By setting a custom filter via `ObjectInputStream.setObjectInputFilter()` or a system-wide `jdk.serialFilter` property, you can whitelist or blacklist classes based on patterns, effectively preventing deserialization attacks without modifying the serialization stream itself.
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.
✗
Override resolveClass in ObjectInputStream
Why it's wrong here
While possible, resolveClass is less flexible and not the preferred pattern in Java 17.
✗
Use SecurityManager with a policy file
Why it's wrong here
SecurityManager is deprecated and does not provide class-level deserialization filtering.
✓
Use ObjectInputFilter with a custom filter
Why this is correct
ObjectInputFilter is the recommended approach to restrict deserialized classes in modern Java.
Related concept
Read the scenario before looking for a memorised answer.
✗
Implement Externalizable and control fields
Why it's wrong here
Externalizable controls serialization but does not prevent deserialization of other objects.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse `resolveClass` (which loads a class) with `ObjectInputFilter` (which filters class resolution), or they assume `SecurityManager` is still the correct tool for this task despite its deprecation in Java 17.
Detailed technical explanation
How to think about this question
The `ObjectInputFilter` API works by intercepting each class resolution during deserialization and applying a filter that can reject classes based on patterns (e.g., `!java.lang.Runtime` to blacklist) or custom logic. Under the hood, the filter is invoked for every object in the stream, including nested objects, allowing fine-grained control. A real-world scenario is a microservice that only expects `com.example.dto.*` classes; a filter like `com.example.dto.**;!*` can reject any unexpected class, mitigating gadget chain attacks.
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 small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
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.
Java I/O API and Securing Applications — This question tests Java I/O API and Securing Applications — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Use ObjectInputFilter with a custom filter — Option C is correct because Java 17 provides the `ObjectInputFilter` API (introduced in Java 9) as the standard mechanism to restrict which classes can be deserialized. By setting a custom filter via `ObjectInputStream.setObjectInputFilter()` or a system-wide `jdk.serialFilter` property, you can whitelist or blacklist classes based on patterns, effectively preventing deserialization attacks without modifying the serialization stream itself.
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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