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Modern Java Patterns in Practice: Records, Pattern Matching, and Switch (with Real Refactors)

Modern Java has evolved into a powerful language for expressive, concise, and safe code, thanks to Records, Pattern Matching, and the new Switch patterns. But understanding why and how to apply these features effectively is what separates elegant refactors from confusing rewrites.

This session walks through real-world before/after examples that show how to simplify legacy code using these new constructs. You will see side-by-side diffs of refactors that replace verbose classes, long instanceof chains, and brittle type hierarchies with clean, declarative patterns. Each example highlights reasoning, trade-offs, and measurable impact from reduced bytecode complexity to easier testing and maintenance.

We will also cover version readiness (GA vs preview features from JDK 21 through 25), build and IDE setup, and pitfalls around mutability, serialization, and JSON mapping. Attendees will leave with a practical migration checklist and a strong grasp of when Records and Pattern Matching truly shine, and when they don’t.

What You Will Learn

• How Records, Record Patterns, and Switch Pattern Matching simplify real codebases

• Common pitfalls and anti-patterns to avoid

• Performance and bytecode insights from actual benchmarks

• Testing and maintenance techniques for pattern-based logic

• A concise migration checklist for applying these features tomorrow

Who Should Attend

Experienced Java developers and architects who want to modernize existing codebases, reduce boilerplate, and confidently adopt new Java language features in production.