Spring Boot 4 Migration Skill

Spring Boot 4 Migration Skill

A comprehensive [Claude Code skill](https://code.claude.com/docs/en/skills) for migrating Spring Boot 3.x applications to Spring Boot 4.x and staying current across 4.x minor versions.

What This Skill Does

When installed, this skill gives Claude Code targeted guidance on the breaking changes documented in the official Spring Boot 4 migration guide and release notes, and walks you through migration step-by-step. It supports:

• Toolchain version check: Detects unsupported Java, Kotlin, Maven, and Gradle versions and guides upgrades before migration begins
• Two migration strategies: All-at-once (9 sequential phases) or gradual upgrade (Day-1 baseline with 6 independent tracks)
• Compatibility bridges: spring-boot-starter-classic, spring-boot-jackson2, spring-security-access for incremental adoption
• Minor version tracking: Bridge removal timelines, deprecation promotions, and new features for 4.1, 4.2, and beyond
• Comprehensive coverage: Build files, modular starters, Jackson 3, properties, package relocations, Spring Security 7, testing (MockitoBean, Testcontainers 2, JUnit 6), Spring Framework 7, Hibernate 7.1, observability (OpenTelemetry, Micrometer, Actuator), API versioning, HTTP interfaces and clients, AOT/native image, JSpecify nullability, resilience (retry, concurrency limiting), Spring for Apache Kafka 4 (KRaft-only @EmbeddedKafka, spring-boot-starter-kafka-test, KIP-848 / KIP-932)
• Verification script: Bridge-aware PASS/FAIL/WARN/BRIDGE checks
• Enterprise rollout: Wave-based strategy for organizations with many services

Installation

Clone the skill into your Claude Code skills directory:

git clone https://github.com/adityamparikh/spring-boot-4-migration-skill.git ~/.claude/skills/spring-boot-4-migration

Claude Code will pick up the skill on the next session.

Usage

In Claude Code, say any of:

• "Migrate this project to Spring Boot 4"
• "Upgrade to Sprin