Use a repeatable Java-to-Clojure migration sequence: choose a seam, preserve behavior with tests, wrap the boundary, move logic into data-first Clojure, and validate before expanding scope.
Successful migration is a process, not a rewrite. The safest approach is to introduce Clojure at a boundary, keep a stable integration contract, and expand the pure core over time.
This section outlines a repeatable sequence: choose a target, lock down behavior with tests, build a thin adapter, migrate logic into Clojure functions over data, then validate in CI and production-like environments.
| Migration step | Review checkpoint |
|---|---|
| Pick a seam | The Java caller and Clojure callee can exchange a stable contract. |
| Preserve behavior | Characterization tests or golden fixtures explain what must not change. |
| Move logic inward | Pure Clojure functions handle decisions while adapters keep I/O and Java types at the edge. |
| Expand scope | Only migrate the next slice after correctness, performance, and team workflow are stable. |