add-benchmarks

To add JMH microbenchmarks to a Spring Boot 4 project, apply the me.champeau.jmh Gradle plugin and dependencies, configure the jmhJar task with zip64 handling, and seed a baseline benchmark class under src/jmh/java to measure throughput on demand.

Use JMH microbenchmarks when you need to measure in-JVM behavior such as method-level performance or harness overhead, rather than HTTP or cross-service load testing. This targets throughput of specific service-method implementations within the JVM.

Yes, the Gradle JMH plugin works with large Spring Boot 4 classpaths by configuring the jmhJar task with zip64 handling. This ensures the benchmark JAR builds correctly despite the large number of dependencies.

To keep JMH benchmarks out of standard Gradle check tasks, the configuration explicitly excludes JMH from tasks.check. This ensures benchmarks run only on-demand via ./gradlew jmh, keeping CI fast.

A seed benchmark class is a baseline *Benchmark.java file generated under src/jmh/java. It establishes a reference point for measuring throughput before you add real domain benchmarks for hot paths like serialization or database queries.