Why Spring

Java 21 + Spring Boot 4 powers most production Korean backends — strong types, mature ecosystem, proven patterns.

By the end:

• Understand multi-module Spring projects
• Treat SQL as SSOT, JPA/MyBatis as readers
• Design REST APIs to spec
• Add JWT authentication
• Write integration tests with @SpringBootTest + Testcontainers
• Deploy with Docker + Caddy

Flow

[1] What is backend ──▶ [2] First project ──▶ [3] SQL = SSOT ──▶ [4] REST design
                                                                      │
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                              [7] Deploy ◀── [6] Testing ◀── [5] JWT auth

Steps 1–4 are how to build it. Steps 5–7 are how to keep it safe and stable.

Prerequisite — getting-started + Java 21 installed.