The answer is composition, specifically the Strategy pattern, because it allows the Report class to delegate format generation to separate objects, enabling new formats like PDF or Excel to be added without modifying the Report class itself. This is the core of the composition over inheritance pattern: instead of locking behavior into a rigid class hierarchy, you compose behavior from interchangeable components. On the Oracle Java Foundations 1Z0-811 exam, this question tests your understanding of object-oriented design principles and how to achieve flexibility without breaking the Open/Closed principle. A common trap is choosing inheritance, which would force you to create a new subclass for every format and tightly couple the Report class to each variant. Remember: inheritance is for "is-a" relationships, but composition is for "has-a" flexibility. Memory tip: think of a printer that accepts different cartridges—you swap the cartridge, not the whole printer.
1Z0-811 Object-Oriented Programming Practice Question
This 1Z0-811 practice question tests your understanding of object-oriented programming. 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 team is designing a system where a 'Report' class can be generated in different formats (PDF, Excel, HTML). They want to avoid modifying the Report class when adding new formats. Which OOP principle or pattern should they use?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Composition
Option A is correct because composition (or Strategy pattern) allows the Report class to delegate format generation to separate objects, enabling easy extension. Option B is wrong because inheritance would create a rigid hierarchy. Option C is wrong because Singleton ensures a single instance, not flexibility. Option D is wrong because method overloading is compile-time and not suitable for adding new formats dynamically.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Method Overloading
Why it's wrong here
Overloading is compile-time and not suitable for runtime format selection.
✓
Composition
Why this is correct
Composing Report with a formatter interface allows adding formats without modifying Report.
Related concept
Static NAT maps one inside address to one outside address.
✗
Inheritance
Why it's wrong here
Inheritance would require creating subclasses for each format, modifying Report if new formats are added.
✗
Singleton
Why it's wrong here
Singleton controls instantiation but does not support extensibility.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related 1Z0-811 NAT questions on configuration and troubleshooting.
Object-Oriented Programming — This question tests Object-Oriented Programming — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: Composition — Option A is correct because composition (or Strategy pattern) allows the Report class to delegate format generation to separate objects, enabling easy extension. Option B is wrong because inheritance would create a rigid hierarchy. Option C is wrong because Singleton ensures a single instance, not flexibility. Option D is wrong because method overloading is compile-time and not suitable for adding new formats dynamically.
What should I do if I get this 1Z0-811 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related 1Z0-811 NAT questions on configuration and troubleshooting.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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Question Discussion
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