Reclazz Spring Boot starter

A starter that makes a Spring Boot app aware of Reclazz: it reports at startup whether the hot-reload agent is attached, gives the exact command to attach it when it is not, and, where the actuator is present, exposes a reclazz endpoint with live status. The coordinate is com.onurkat.reclazz:reclazz-spring-boot-starter.

What it does not do

It does not attach the agent. A -javaagent has to be on the command line when the JVM starts, and a starter runs after that, so nothing a dependency does can turn the agent on by itself. Attaching is the job of the Gradle plugin, the Maven plugin, or a plain flag; see gradle-plugin.md, maven.md and for-ai-agents.md. The starter is the Spring-native half: it tells you whether that worked and surfaces the status.

Add it

dependencies {
    developmentOnly("com.onurkat.reclazz:reclazz-spring-boot-starter:1.4.0")
}

developmentOnly keeps it out of the production jar, which is the right scope: it is a development aid. On Maven, use an optional or a dev-profile dependency.

With the agent attached, the log at startup reads:

Reclazz hot-reload agent is attached. Edit code, recompile, and changes reload in place, no restart.

Without it, the starter says so and prints how to attach it, rather than staying silent while nothing reloads.

Configuration

All properties are under the reclazz prefix.

Scope it to development the usual Spring way, for example by keeping the dependency developmentOnly, or by setting reclazz.enabled per profile. Turning fail-on-missing-agent on in a dev profile makes a hot-reload run required there: the app refuses to start without the agent.

The actuator endpoint

When spring-boot-actuator is on the classpath, the starter registers a reclazz endpoint. Expose it like any other:

management.endpoints.web.exposure.include=reclazz

GET /actuator/reclazz

{
  "attached": true,
  "agentFlag": "-javaagent:/.../reclazz-agent-1.4.0.jar=platform=spring",
  "agent": "1.4.0",
  "protocol": 1,
  "port": 52227,
  "health": ["Reloads: 3, failures: 0, median 12ms"]
}

When the agent is not attached it returns {"attached": false}. The endpoint reads the agent's loopback status socket and reaches nothing off the machine, the same promise the agent itself keeps.

How attachment is detected

The starter reads this JVM's own startup arguments (RuntimeMXBean.getInputArguments()) and looks for a -javaagent that names the Reclazz agent. It asks the agent nothing and opens no socket for the check; the status socket is used only by the actuator endpoint, and only to loopback.