Jan_Prep_2025.md

ChatGPT Prompt for detailed PREP plan

Create a detailed 3-week preparation plan for a Java backend developer with 3 years of experience in Spring Boot, databases (SQL/NoSQL), Jenkins, JSON, Kafka, and Git. The person had a 2-month career gap and wants to regain confidence, practice hands-on coding, and prepare for technical interviews to secure a backend developer job. The plan should:

Be broken down week-by-week and day-by-day.

Cover technical refreshers (Java, Spring Boot, REST APIs, databases, Kafka, Git, CI/CD).

Include coding practice (DSA/LeetCode-style) and small project tasks.

Add interview prep (mock interviews, behavioral questions, system design discussions).

Suggest confidence-building activities and ways to track progress.

Be realistic and achievable in ~2–3 hours daily (since she may not have full-time availability).
Output should be structured and actionable so she can follow it step by step."*

📝 Assignment: Build a User Management API with Spring Boot

Objective

Create a Spring Boot REST service that proxies selected endpoints from ReqRes API and exposes them under your own /api namespace. Implement GET users, GET user by ID, and Update user functionality with proper validation, error handling, and documentation.

Here Request and Response structures: https://reqres.in/api-docs/#/

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Requirements

1. Endpoints (your service should provide)

• GET /api/users

  • Fetch users from ReqRes (GET https://reqres.in/api/users).

• GET /api/users/{id}

  • Fetch a single user (GET https://reqres.in/api/users/{id}).
  • Return 404 if user not found.

• PUT /api/users/{id}

  • Update user data (PUT https://reqres.in/api/users/{id}) with JSON body:

    {
      "name": "Jane Doe",
      "job": "Developer"
    }

  • Forward request to ReqRes and return response.

  • Validate request body (name & job not blank).

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2. Functional Requirements

• Input validation:

  • page >= 1, id > 0.
  • Request body must contain name and job.

• Error handling:

  • If ReqRes returns 404 → return 404 { "error": "User not found" }.
  • If validation fails → return 400 { "error": "Invalid input" }.

• Logging:

  • Log request method, URL, and response time for outgoing ReqRes calls.

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3. Non-Functional

• Use WebClient (preferred) or RestTemplate for outbound calls.
• Timeout 3s for ReqRes calls.
• Return JSON with appropriate status codes.
• Document endpoints with Swagger/OpenAPI.
• Write at least 3–4 unit tests (happy path, validation fail, ReqRes 404).

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4. Bonus (Optional Enhancements)

• Add pagination support with validation in GET /api/users?page={page}.
• Cache results of GET /api/users?page=1 for 30 seconds.
• Add integration test hitting real ReqRes API.
• Dockerize the application.

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5. Acceptance Criteria (Definition of Done)

• ✅ GET /api/users?page=2 returns list of users from ReqRes.
• ✅ GET /api/users/2 returns correct user JSON.
• ✅ PUT /api/users/2 accepts valid JSON body and forwards update to ReqRes.
• ✅ Error cases (bad page/id, not found, missing body fields) return appropriate error JSON.
• ✅ Swagger available at /swagger-ui.html.
• ✅ Unit tests pass.
• ✅ README with run instructions + sample curl commands.

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Example Usage

# List users (page=2)
curl -s http://localhost:8080/api/users?page=2 | jq

# Get single user
curl -s http://localhost:8080/api/users/2 | jq

# Update user
curl -X PUT http://localhost:8080/api/users/2 \
  -H "Content-Type: application/json" \
  -d '{"name": "Jane Doe", "job": "Developer"}' | jq

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👉 This way she gets to practice GET, path variables, query params, PUT with request body, validation, error handling, logging, and Swagger — a mini but realistic backend task.

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Resources

• SQL Preparation Website (https://datalemur.com/questions/python-compound-interest)