Java Spring Boot — Lesson 2: REST APIs, Validation, Error Handling, Documentation, and Client Integration

Technical Scope

• Spring MVC controllers, request mapping, DTOs, serialization, and content negotiation
• Bean Validation, custom validators, request constraints, and error responses
• exception handlers, status codes, problem details, and correlation IDs
• OpenAPI documentation, pagination, versioning, testing, and API compatibility

Instructor Demonstration

Demonstrate Spring MVC controllers, request mapping, DTOs, serialization, and content negotiation within a secure order-management REST service built with Spring Boot, persisted transactionally, tested across layers, observed in production, and packaged for container deployment, then capture the exact configuration, command, transaction, report, trace, or code evidence that proves the expected result.

Applied Workshop

Implement a controlled workshop covering Bean Validation, custom validators, request constraints, and error responses and exception handlers, status codes, problem details, and correlation IDs, then test a failure, exception, or business-control scenario involving OpenAPI documentation, pagination, versioning, testing, and API compatibility.

1. Confirm the environment, identities, data, dependencies, controls, and expected result.
2. Complete the product-specific configuration, development, analysis, or business-process task.
3. Capture commands, configuration, output, logs, transactions, reports, or test evidence.
4. Explain the operational, security, performance, data-quality, or business trade-off.

Validation Standard

The REST APIs, Validation, Error Handling, Documentation, and Client Integration result must be reproducible, traceable to approved inputs, and consistent with expected Oracle product or business-process behavior.

• The intended target, scope, and ownership are verified.
• The result is supported by reproducible evidence and expected-value checks.
• Security, performance, reliability, data quality, and support impact are reviewed.
• Unexpected behavior is investigated before acceptance or release.

Failure Analysis

Diagnose issues in Spring MVC controllers, request mapping, DTOs, serialization, and content negotiation, Bean Validation, custom validators, request constraints, and error responses, exception handlers, status codes, problem details, and correlation IDs, or OpenAPI documentation, pagination, versioning, testing, and API compatibility without making an unverified production change.

Learners isolate the smallest proven cause, apply a reversible correction, rerun validation, and record the preventive action.

Practical Outcome

Complete a validated implementation or analysis for REST APIs, Validation, Error Handling, Documentation, and Client Integration and defend the result with documented evidence.