Mastering Microservices with Spring Boot and Spring Cloud — Lesson 1: Microservice boundaries, domain decomposition, Spring Boot services, REST contracts, DTOs, validation, persistence choices, transactions, and test strategy

Learning Objectives

• Identify the architecture and operational choices that shape Microservice boundaries, domain decomposition, Spring Boot services, REST contracts, DTOs, validation, persistence choices, transactions, and test strategy.
• Run normal and boundary tests and record the outcome in service-boundary model and API contract test suite.
• Separate root cause from symptom when investigating a shared database coupling services that are intended to deploy independently.

Detailed Topics

• Microservice boundaries
• Domain decomposition
• Spring Boot services
• REST contracts
• DTOs
• Validation
• Persistence choices
• Transactions
• And test strategy
• Decision ownership, prerequisites, and acceptance evidence for Microservice boundaries, domain decomposition, Spring Boot services, REST contracts, DTOs, validation, persistence choices, transactions, and test strategy
• Relevant access, security, capacity, dependency, performance, recovery, and support considerations

Instructor Demonstration

The instructor builds a representative scenario for Microservice boundaries, domain decomposition, Spring Boot services, REST contracts, DTOs, validation, persistence choices, transactions, and test strategy, narrating each decision and showing how it contributes to a resilient microservices solution built with Spring Boot and Spring Cloud, supported by service discovery, configuration management, observability, secure APIs, and controlled deployment. The demonstration records service-boundary model and API contract test suite so learners can compare design intent with observable behavior.

Hands-On Exercise

Work through a role-based scenario involving Microservice boundaries, domain decomposition, Spring Boot services, REST contracts, DTOs, validation, persistence choices, transactions, and test strategy. Validate the expected path, test “a shared database coupling services that are intended to deploy independently,” choose the safest corrective action, and capture the reasoning and outcome in service-boundary model and API contract test suite.

1. Confirm scope, access, sample workloads, and acceptance criteria.
2. Perform the configuration or operation using a controlled sequence.
3. Inspect outputs and downstream effects rather than relying on task status alone.
4. Close with a support note, preventive action, and reproducible validation step.

Scenario Analysis

• Clarify the service trigger, affected components and roles, prerequisites, and acceptable result for Microservice boundaries, domain decomposition, Spring Boot services, REST contracts, DTOs, validation, persistence choices, transactions, and test strategy.
• Compare at least two implementation or correction choices and identify which evidence would distinguish them.
• Decide how service-boundary model and API contract test suite should be reviewed, approved, retained, and handed to the next owner.

Troubleshooting Guidance

Diagnose Microservice boundaries, domain decomposition, Spring Boot services, REST contracts, DTOs, validation, persistence choices, transactions, and test strategy by checking effective state, ownership, dependencies, health, logs, and recent changes. Use service-boundary model and API contract test suite to locate the earliest divergence. Treat “a shared database coupling services that are intended to deploy independently” as a hypothesis until the same test passes after correction and under a boundary condition.

Validation Checklist

• Configuration and source state used for Microservice boundaries, domain decomposition, Spring Boot services, REST contracts, DTOs, validation, persistence choices, transactions, and test strategy are versioned or otherwise traceable.
• Service-boundary model and api contract test suite shows both baseline and accepted result.
• Security, performance, dependency, and resilience side effects are considered where relevant.
• Recovery steps and handover notes are usable by an operations practitioner.

Lesson Outcome

Learners can apply Microservice boundaries, domain decomposition, Spring Boot services, REST contracts, DTOs, validation, persistence choices, transactions, and test strategy, explain the decisions made, and defend the result with service-boundary model and API contract test suite.