Ankur Mhatre
86246dc860
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
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← Why your profile file lost · Index · Config trees →
5. spring.config.import
Transcript: 04-import-and-multidoc.txt.
spring:
config:
import: "optional:classpath:/imported.yaml"
The imported file wins
This is the part that catches people, and it catches them in the direction opposite to the one they brace for:
effective value : from-imported-yaml
1. from-imported-yaml <- imported.yaml
2. from-application-import-yaml <- application-import.yaml (declared the import)
3. from-application-yaml <- application.yaml
The importing file declared the import and then lost to it. An imported document is processed after the document that declared it, and later documents win.
#include semantics would give the opposite. So would treating the import as a set of
defaults, which is what people usually intend when they import a shared baseline. If you import
a company-wide common.yaml expecting your own file to override it, every key common.yaml
sets will quietly beat yours.
To get defaults-style behaviour, put your overrides somewhere that outranks config data — an environment variable or a command-line argument — or import from a later document in your own file so the ordering is explicit.
Prefixes
| Prefix | Meaning |
|---|---|
optional: |
do not fail if it is missing |
file: |
a filesystem path |
classpath: |
a classpath resource |
configtree: |
a directory of value-per-file entries |
They compose: optional:configtree:/etc/config/.
Without optional:, a missing location is ConfigDataLocationNotFoundException at startup.
That is usually what you want for a secret mount and never what you want for a developer
machine.
Where imports are legal
spring.config.import is only honoured in config data — application.yaml and friends. Setting
it as an environment variable or a command-line argument works too, because those are processed
before config data is loaded. Setting it anywhere else does nothing.
Imports are processed depth-first, and a cycle is detected and reported rather than looping.