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 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Gip4srpzMwjgoba6uEfbr5

configuration-properties/src/main/resources/application-badvalidation.yaml

@@ -0,0 +1,12 @@
+demo:
+  validated:
+    # @NotBlank -- blank is exactly what it rejects.
+    name: "  "
+    # @Min(1) @Max(65535)
+    port: 99999
+    # @Pattern(regexp = "https?://.*")
+    endpoint: "ftp://files.example.com"
+    pool:
+      # @Min(1) @Max(100) on a nested record. Only checked because the component
+      # carries @Valid; without it this passes.
+      size: 4000

configuration-properties/src/main/resources/application-csvlist.yaml

@@ -0,0 +1,7 @@
+# Overrides the YAML block list in application.yaml with a comma-separated string.
+# demo.csvlist.loaded is a marker so the transcript can prove this file was read.
+demo:
+  csvlist:
+    loaded: "yes"
+  mail:
+    recipients: "[email protected],[email protected],[email protected]"

configuration-properties/src/main/resources/application.yaml

@@ -0,0 +1,37 @@
+spring:
+  application:
+    name: configuration-properties
+
+server:
+  port: 8080
+
+logging:
+  level:
+    root: WARN
+    com.ankurm: INFO
+
+demo:
+  mail:
+    host: smtp.example.com
+    # port omitted on purpose: @DefaultValue("587") supplies it.
+    timeout: 45s
+    retries:
+      max-attempts: 5
+      backoff: 1500ms
+    # A YAML block list. @ConfigurationProperties binds this; @Value("${demo.mail.recipients}")
+    # does not -- see docs/output/03-value-vs-binding.txt.
+    recipients:
+      - [email protected]
+      - [email protected]
+    headers:
+      X-Env: demo
+      X-Team: platform
+  # demo.relaxed.api-key is deliberately NOT set here. scripts/demo-env-binding.sh supplies
+  # it as an operating-system environment variable, one spelling at a time, and a value in
+  # this file would mask the env var and make every row of the matrix say "bound".
+  validated:
+    name: demo-service
+    port: 8443
+    endpoint: https://api.example.com
+    pool:
+      size: 25