Three new article modules: configuration binding, profiles and config data, Spring AOP

configuration-properties/  @ConfigurationProperties vs @Value on Spring Boot 4.1.1.
  The relaxed-binding matrix is generated by binding each spelling rather than
  transcribed, and re-checked against real processes -- the in-process probe was
  wrong twice before it was right. Records the three findings that came out of it:
  @Value does get relaxed resolution inside Spring Boot (Boot attaches
  ConfigurationPropertySources), the configuration processor silently stops
  generating metadata on JDK 23+ when declared as a plain dependency, and @Valid is
  not what makes nested constraints run.

profiles-and-config/       Precedence, profiles, spring.config.import and config trees.
  /precedence reports every source holding a property in rank order with file and
  line, which turns "my profile file had no effect" into a two-line answer. Also
  pins the counterintuitive one: an imported file outranks the file that imported it.

spring-aop/                Designators, proxy types, and aspects that do not fire.
  One advice per supported designator so the reference table is generated from real
  matches; all fourteen unsupported designators fed to the parser. Two corrections to
  the reference documentation: unsupported designators throw
  UnsupportedPointcutPrimitiveException (extends RuntimeException, not
  IllegalArgumentException), and spring-boot-starter-aop was renamed to
  spring-boot-starter-aspectj in Boot 4.

19 contract tests across the three modules, 15 captured transcripts, all regenerated
by scripts/run-all.sh. Verified on Spring Boot 4.1.1, Spring Framework 7.0.9,
JDK 25.0.4.1.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gip4srpzMwjgoba6uEfbr5

profiles-and-config/scripts/env.sh

@@ -0,0 +1,76 @@
+#!/usr/bin/env bash
+# Shared environment. Point JAVA_HOME at a JDK 25 (or newer) installation.
+: "${JAVA_HOME:?set JAVA_HOME to a JDK 25+ installation}"
+export PATH="$JAVA_HOME/bin:$PATH"
+MVN="${MVN:-mvn}"
+JAR="target/profiles-and-config-1.0.0.jar"
+APP_MAIN="com.ankurm.profiles.ProfilesApplication"
+APP_PORT="${APP_PORT:-8080}"
+
+# Strip environment noise that is an artefact of the machine, not of Spring:
+# the JVM prints a JAVA_TOOL_OPTIONS banner to stderr on every launch when a proxy
+# truststore is configured, and it would otherwise end up in every committed transcript.
+clean() { grep -v "Picked up JAVA_TOOL_OPTIONS" | grep -v "^OpenJDK 64-Bit Server VM warning"; }
+
+# Start the demo jar detached, record its PID, and block until it answers.
+# Extra arguments are passed to the application. Environment variables for the run are
+# passed by setting them on the call: `APP_ENV="A=1 B=2" start_app --spring.profiles.active=x`
+start_app() {
+  stop_app
+  mkdir -p target
+  # Deliberately NOT setsid: setsid forks when it is not already a process-group leader,
+  # so $! would be the PID of a process that exits immediately and the JVM would survive
+  # every later stop_app. A surviving JVM keeps the port, the next scenario fails to bind,
+  # and curl answers from the previous scenario -- which reads exactly like the
+  # configuration change under test having had no effect. Three wrong findings in this
+  # repository came from that before it was tracked down.
+  if [ -n "${APP_ENV:-}" ]; then
+    # shellcheck disable=SC2086
+    env $APP_ENV nohup java -jar "$JAR" "$@" > /tmp/profiles-demo.log 2>&1 < /dev/null &
+  else
+    nohup java -jar "$JAR" "$@" > /tmp/profiles-demo.log 2>&1 < /dev/null &
+  fi
+  echo $! > target/app.pid
+  for _ in $(seq 1 60); do
+    curl -s -o /dev/null "http://127.0.0.1:${APP_PORT}/precedence" 2>/dev/null && return 0
+    kill -0 "$(cat target/app.pid)" 2>/dev/null || { echo "JVM exited during startup:"
+      tail -20 /tmp/profiles-demo.log; return 1; }
+    sleep 1
+  done
+  echo "application did not answer"; tail -20 /tmp/profiles-demo.log; return 1
+}
+
+# Stop it by recorded PID. Never by pattern: `ps | grep <jar name>` also matches the shell
+# running the script, because the jar name is on that shell's own command line.
+stop_app() {
+  if [ -f target/app.pid ]; then
+    pid=$(cat target/app.pid)
+    if [ -n "$pid" ] && grep -qa "profiles-and-config" "/proc/$pid/cmdline" 2>/dev/null; then
+      kill -9 "$pid" 2>/dev/null || true
+      wait "$pid" 2>/dev/null || true      # reap, so bash prints no "Killed" notice
+    fi
+    rm -f target/app.pid
+  fi
+  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
+}
+
+# Print the precedence report for one property, compactly.
+report() {
+  curl -s "http://127.0.0.1:${APP_PORT}/precedence?name=$1" | python3 -c '
+import json,sys
+d=json.load(sys.stdin)
+print("  active profiles :", ", ".join(d["activeProfiles"]) or "(none)")
+print("  effective value :", d["effectiveValue"])
+for h in d["holders"]:
+    src=h["source"]
+    for noisy,short in (("Config resource \x27class path resource [","file "),
+                        ("\x27 via location \x27optional:classpath:/\x27}","")):
+        src=src.replace(noisy,short)
+    src=src.replace("OriginTrackedMapPropertySource {name=","").replace("]","")
+    print("    %d. %-34s <- %s" % (h["rank"], h["value"], src.strip()))
+print("  holders that lost:", d["shadowedCount"])'
+}