Spring Boot 4 Actuator in production: endpoints, security, custom health indicators

Companion repository for the ankurm.com article. Every transcript in docs/output/
was produced by running this project; scripts/run-all.sh regenerates all of them.

Verified against Spring Boot 4.1.1 / Framework 7.0.9 / Security 7.1.1 /
Micrometer 1.17.1 / kafka-clients 4.2.1 on Temurin JDK 25.0.4.1+1.

scripts/stop.sh

@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+# Kill by main class, never by a pattern that could match this script's own command line.
+# `pkill -f spring-boot` matches the shell running it and takes the terminal with it.
+set -u
+for p in $(ps -eo pid,args | grep '[A]ctuatorProductionApplication' | awk '{print $1}'); do
+  kill -9 "$p" 2>/dev/null || true
+done
+# Wait for the port to actually close. Killing the PID is not the same as the socket being
+# free, and a stale listener looks exactly like your configuration change having no effect.
+for _ in $(seq 1 40); do
+  if ! (exec 3<>/dev/tcp/127.0.0.1/"${APP_PORT:-8080}") 2>/dev/null; then break; fi
+  sleep 0.25
+done
+exec 3<&- 2>/dev/null || true