✔JVM and GC tuning: G1GC region tuning or ZGC migration for sub-millisecond pause times, measured in production.
✔GridGain in-memory computing: pricing rules, sessions, and reference data served at microsecond access times.
✔Kafka consumer optimisation: partition sizing, batch fetch tuning, and virtual threads to eliminate consumer lag.
✔HikariCP connection pool tuning: sized to measured concurrency, eliminating exhaustion without over-provisioning.
✔Async and reactive patterns: Java 21 virtual threads or Spring WebFlux for high-concurrency APIs.
✔Continuous performance testing: Gatling load tests in CI/CD catch regressions before they reach production.