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Best Practices for Interoperability

Design the boundary: isolate Java types, handle nulls, avoid reflection, and keep the core idiomatic.

Interop is easiest to maintain when it is treated as an architectural boundary, not a convenience hack.

For Java engineers, a useful checklist:

  • Localize interop in a small set of namespaces.
  • Convert types once at the edge; keep your core on persistent data.
  • Handle null defensively and decide on a clear nil convention.
  • Avoid reflection in hot paths (type hints when needed; measure first).
  • Keep effects explicit (resource lifecycles, thread pools, blocking calls).

If you get the boundary right, you can use Java libraries aggressively without losing the benefits that brought you to Clojure in the first place.

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Revised on Friday, April 24, 2026