200-901 Cisco Platforms and Development Practice Question
This 200-901 practice question tests your understanding of cisco platforms and development. 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 developer is using Cisco NSO to create a service. They are evaluating whether to use Python or Java for plan callbacks. Which consideration is most important?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Both are equally supported, but Python has more extensive libraries for networking
Option C is correct because Cisco NSO supports both Python and Java for plan callbacks, and the choice between them often hinges on the developer's familiarity and the specific requirements of the service. Python is particularly favored in many networking contexts due to its extensive ecosystem of libraries (e.g., for NETCONF, RESTCONF, or SNMP), which can accelerate development. However, Java is equally supported and may be chosen for performance-critical or deeply integrated components within NSO's Java Native Interface (JNI).
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.
✗
Java is preferred due to better integration with NSO's internal data model
Why it's wrong here
Both have equivalent integration capabilities.
✗
Python is the only supported language for custom service code in NSO
Why it's wrong here
NSO supports both Python and Java.
✓
Both are equally supported, but Python has more extensive libraries for networking
Why this is correct
Python's rich ecosystem and readability make it a common choice.
Related concept
Read the scenario before looking for a memorised answer.
✗
Python is preferred due to faster execution
Why it's wrong here
Python is generally slower than Java for execution.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that Python is the only or primary language for NSO customizations, when in fact both Python and Java are fully supported, and the choice depends on factors like library availability and developer expertise, not exclusivity or raw performance.
Detailed technical explanation
How to think about this question
Under the hood, NSO uses a Java-based core (the NSO Java VM) for its management agents and data model handling, while Python callbacks run in a separate Python VM via the NSO Python VM integration. This means Java callbacks can directly access NSO's internal Java objects (e.g., Maapi, TransAPI) without serialization overhead, but Python callbacks benefit from a simpler development workflow and dynamic typing. In real-world scenarios, a service that requires heavy data manipulation or tight coupling with NSO's transaction system might lean toward Java, while a service that integrates with external Python-based tools (e.g., Ansible, custom scripts) would favor Python.
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.
Cisco Platforms and Development — This question tests Cisco Platforms and Development — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Both are equally supported, but Python has more extensive libraries for networking — Option C is correct because Cisco NSO supports both Python and Java for plan callbacks, and the choice between them often hinges on the developer's familiarity and the specific requirements of the service. Python is particularly favored in many networking contexts due to its extensive ecosystem of libraries (e.g., for NETCONF, RESTCONF, or SNMP), which can accelerate development. However, Java is equally supported and may be chosen for performance-critical or deeply integrated components within NSO's Java Native Interface (JNI).
What should I do if I get this 200-901 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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