D288 ITSW 3175 Back End Programming - Objective Assessment - WGU 2025

D288 ITSW 3175 Back End Programming

Objective Assessment Review

(Questions & Solutions)

2025




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, Question 1
A cloud-based distributed application must balance consistency,
availability, and partition tolerance. According to the CAP theorem, which
of the following is true?
- A. All three guarantees can be fully achieved simultaneously.
- B. Only two out of the three guarantees can be achieved at any given
time.
- C. Consistency and availability are mutually exclusive regardless of
network partitions.
- D. Partition tolerance can be ignored if high availability is required.

ANS: B
Rationale: The CAP theorem states that in distributed systems, only
two out of the three guarantees—Consistency, Availability, and Partition
Tolerance—can be achieved simultaneously. Designers must make
tradeoffs, particularly in the presence of network partitions.

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Question 2
A microservices architecture is designed for a high-traffic e-commerce
platform. To minimize inter-service latency, which communication
pattern is most appropriate for critical operations?
- A. Synchronous HTTP REST calls
- B. Asynchronous messaging (e.g., via message queues)
- C. Periodic batch processing via scheduled tasks
- D. Remote Procedure Calls (RPC) over SOAP

ANS: B
Rationale: Asynchronous messaging decouples services and reduces
latency by avoiding blocking calls. For real-time, high-traffic systems,
message queues (or similar event-driven patterns) are preferred over
synchronous patterns.
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Question 3
In designing a RESTful API for a complex data service, which HTTP
method is generally used for partial updates of a resource?
- A. GET
- B. POST
- C. PATCH
- D. DELETE

ANS: C
Rationale: The PATCH method is intended for partial updates of
resources. Unlike PUT, which typically replaces an entire resource, PATCH
allows clients to submit only the data that needs modification.

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Question 4
A back-end developer is implementing caching to reduce load on a
relational database. Which of the following is a common in-memory data
store used as a cache?
- A. Apache Kafka
- B. Redis
- C. MongoDB
- D. Hadoop

ANS: B
Rationale: Redis is a widely used in‑memory data store that supports
various caching strategies. It improves performance by reducing database
load and latency.

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Question 5
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, Which distributed transaction management protocol is used to ensure
atomicity across multiple services?
- A. Two‑phase commit
- B. Peer-to-peer replication
- C. Eventual consistency
- D. Load balancing

ANS: A
Rationale: The two‑phase commit protocol is a classic approach to
distributed transaction management. It ensures that a transaction either
commits on all nodes or rolls back entirely, preserving atomicity.

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Question 6
A development team is tasked with containerizing a legacy application.
What is the major benefit of deploying the application in containers using
orchestration platforms like Kubernetes?
- A. It guarantees a 100% bug‑free deployment.
- B. It simplifies scaling and management through automation and self-
healing.
- C. It eliminates the need for resource monitoring.
- D. It converts the application into a microservice automatically.

ANS: B
Rationale: Container orchestration platforms (e.g., Kubernetes)
automate deployment, scaling, and management of containerized
applications. They provide features like self‑healing, automated rollouts,
and scaling, making management easier and more resilient.

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Question 7
When building a high-performance back-end in Java, which of the
following techniques is most effective for handling concurrency in server
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