upgrade

name: upgrade description: Upgrade Java runtime versions, frameworks, and dependencies to their latest compatible releases

Upgrade Java runtime versions, frameworks, and dependencies.

For detailed, JEP-by-JEP upgrade instructions, see the version-specific skills:

Java 8 → 11 — Module system, removed Java EE modules, var, HTTP Client
Java 11 → 17 — Records, Sealed Classes, Pattern Matching, Text Blocks
Java 17 → 21 — Virtual Threads, Pattern Matching for switch, Record Patterns
Java 21 → 25 — Flexible Constructors, Stream Gatherers, Class-File API

Analyze first — Scan the project structure, build files (pom.xml, build.gradle), and source code to determine current Java version, framework versions, and dependency versions.
Generate an upgrade plan — Produce a plan detailing what will be upgraded and what breaking changes to expect. Present the plan for review.
Apply changes incrementally — Make changes in logical groups:
- Build configuration (Java version, plugin versions)
- Dependencies (framework BOMs, library versions)
- Source code (API changes, deprecated method replacements)
- Configuration files (property renames, format changes)
Validate after each group — Run the build (mvn clean compile or gradle build) to confirm changes compile successfully. Run tests if available.
Check for vulnerabilities — After upgrading, scan for known vulnerabilities in the updated dependencies.

Prefer incremental upgrades over large version jumps when the gap is significant.
Always explain what changes are being made and why.
If a build fails after changes, analyze the error and attempt to fix it before reporting.
When multiple upgrade paths exist, present options and let the developer decide.