What if upgrading a legacy Java app from Java 8 to Java 25 took 20 minutes instead of weeks? In this episode, watch as GitHub Copilot's app modernization extension automatically generates an upgrade plan, applies changes in milestones using OpenRewrite, runs tests, validates CVEs, and checks for behavior changes — all while you supervise.

In this episode, you'll learn:
→ How to use the GitHub Copilot app modernization extension in IntelliJ to upgrade Java runtime and frameworks
→ How the tool breaks major version jumps into safe, incremental milestones (Java 8 → 21 → 25, Spring Boot 1.5 → 3.3 → 3.4 → 3.5)
→ How AI agents use proven open-source tools like OpenRewrite under the hood
→ How automatic CVE scanning and behavior validation catch issues after every change
→ How the agent iterates on test failures — fixing Mockito compatibility changes, dependency issues, and more
→ What happens when a target version isn't fully supported yet (and how the tool explains why)

📺 This is Episode 2 of the Modernize Java Apps with AI series — a 9-part, hands-on guide to upgrading legacy Java applications using GitHub Copilot.

🔗 Series playlist: https://www.youtube.com/playlist?list=PLlrxD0HtieHhaBJWlcxGd-kTDikSD4xyD
🔗 GitHub Copilot Modernization extension: https://aka.ms/GHCPMod-Java

👤 Presented by Sandra Ahlgrimm, Java & AI Advocate, Microsoft

Java #GitHubCopilot #JavaUpgrade #SpringBoot #JakartaEE #OpenRewrite #CVE #JavaModernization #AI #LegacyCode

Microsoft Developer

A walkthrough of using GitHub Copilot's agentic upgrade feature in IntelliJ to migrate a legacy Spring Boot 1.5.9 / Java 8 application all the way to Spring Boot 3.5.3 and Java 25. The process uses OpenRewrite under the hood and proceeds through multiple milestones (Java 21 → 25, Spring Boot 3.3 → 3.4 → 3.5), running CVE checks and all 96 tests at each step. Minor Mockito 5.x compatibility issues are resolved automatically by the agent, and the full upgrade completes in roughly 20 minutes.

Upgrade Java, Spring, and Jakarta EE with GitHub Copilot