Jackson 2 to Jackson 3 Migration Guide: Step-by-Step Upgrade for Java Projects
A complete, step-by-step guide to migrating from Jackson 2.x to Jackson 3.1.2 — covering the tools.jackson group ID and package rename, the unchecked JacksonException change, removed APIs, ObjectMapper to JsonMapper builder migration, custom serialiser renames, and Spring Boot 3/4 coexistence.