application.properties ouside the packaged jar not found

[membersound]

I want to create a "commons" jar that I can include in all of my projects, and that sets some defaults for spring (configuration, logging, etc).
I started trying to disable spring.main.banner-mode. But that does not even work.

The docs state that it should be possible to make use of application.properties outside the jar:
https://docs.spring.io/spring-boot/reference/features/external-config.html

How can I then define those properties in a commons lib?

The following shows the code of my commons lib:

@AutoConfiguration
//@PropertySource("classpath:application.properties") //also not working
public class CommonsConfig {
    @Value("${spring.main.banner-mode}")
    private String bannerMode;

    public CommonsConfig() {
        System.out.println("CommonsConfig LOADED with banner=" + bannerMode); //bannerMode 'null' here
    }
}

With:

/src/main/resources/application.properties:

spring.main.banner-mode=OFF
#logging.group...
#logging.charset.file=

org.springframework.boot.autoconfigure.AutoConfiguration.imports:

org.example.CommonsConfig

Result:

2025-01-22 11:57:55.983 ERROR 162899 --- [           main] o.s.b.SpringApplication                  : Application run failed

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.example.logging.CommonsConfig': Injection of autowired dependencies failed
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:515) ~[spring-beans-6.2.0.jar:6.2.0]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1435) ~[spring-beans-6.2.0.jar:6.2.0]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:600) ~[spring-beans-6.2.0.jar:6.2.0]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:523) ~[spring-beans-6.2.0.jar:6.2.0]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:336) ~[spring-beans-6.2.0.jar:6.2.0]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:288) ~[spring-beans-6.2.0.jar:6.2.0]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:334) ~[spring-beans-6.2.0.jar:6.2.0]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-6.2.0.jar:6.2.0]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.instantiateSingleton(DefaultListableBeanFactory.java:1122) ~[spring-beans-6.2.0.jar:6.2.0]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingleton(DefaultListableBeanFactory.java:1093) ~[spring-beans-6.2.0.jar:6.2.0]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:1030) ~[spring-beans-6.2.0.jar:6.2.0]
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:987) ~[spring-context-6.2.0.jar:6.2.0]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:627) ~[spring-context-6.2.0.jar:6.2.0]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:752) [spring-boot-3.4.0.jar:3.4.0]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:439) [spring-boot-3.4.0.jar:3.4.0]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:318) [spring-boot-3.4.0.jar:3.4.0]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1361) [spring-boot-3.4.0.jar:3.4.0]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1350) [spring-boot-3.4.0.jar:3.4.0]
	at org.example.Main.main(Main.java:14) [classes/:?]
Caused by: org.springframework.util.PlaceholderResolutionException: Could not resolve placeholder 'spring.main.banner-mode' in value "${spring.main.banner-mode}"
	at org.springframework.util.PlaceholderResolutionException.withValue(PlaceholderResolutionException.java:81) ~[spring-core-6.2.0.jar:6.2.0]
	at org.springframework.util.PlaceholderParser$ParsedValue.resolve(PlaceholderParser.java:416) ~[spring-core-6.2.0.jar:6.2.0]
	at org.springframework.util.PlaceholderParser.replacePlaceholders(PlaceholderParser.java:128) ~[spring-core-6.2.0.jar:6.2.0]
	at org.springframework.util.PropertyPlaceholderHelper.parseStringValue(PropertyPlaceholderHelper.java:118) ~[spring-core-6.2.0.jar:6.2.0]
	at org.springframework.util.PropertyPlaceholderHelper.replacePlaceholders(PropertyPlaceholderHelper.java:114) ~[spring-core-6.2.0.jar:6.2.0]
	at org.springframework.core.env.AbstractPropertyResolver.doResolvePlaceholders(AbstractPropertyResolver.java:255) ~[spring-core-6.2.0.jar:6.2.0]
	at org.springframework.core.env.AbstractPropertyResolver.resolveRequiredPlaceholders(AbstractPropertyResolver.java:226) ~[spring-core-6.2.0.jar:6.2.0]
	at org.springframework.context.support.PropertySourcesPlaceholderConfigurer.lambda$processProperties$0(PropertySourcesPlaceholderConfigurer.java:201) ~[spring-context-6.2.0.jar:6.2.0]
	at org.springframework.beans.factory.support.AbstractBeanFactory.resolveEmbeddedValue(AbstractBeanFactory.java:963) ~[spring-beans-6.2.0.jar:6.2.0]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1536) ~[spring-beans-6.2.0.jar:6.2.0]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1514) ~[spring-beans-6.2.0.jar:6.2.0]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.resolveFieldValue(AutowiredAnnotationBeanPostProcessor.java:785) ~[spring-beans-6.2.0.jar:6.2.0]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:768) ~[spring-beans-6.2.0.jar:6.2.0]
	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:146) ~[spring-beans-6.2.0.jar:6.2.0]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:509) ~[spring-beans-6.2.0.jar:6.2.0]
	... 18 more

[wilkinsona]

Given the above, your common library's application.properties aren't going to be outside the packaged jar, they're going to be in the common library's jar and therefore part of the classpath. As such, they'll be subject to usual class path ordering and will likely be hidden by your application's own application.properties file that will be available earlier on the classpath.

The locations are described here:

1. From the classpath
   a. The classpath root
   b. The classpath /config package
2. From the current directory
   a. The current directory
   b. The config/ subdirectory in the current directory
   c. Immediate child directories of the config/ subdirectory

"Outside the packaged jar" is referring to 2 in this list. The files have to be available on the file system, not inside a (nested) jar on the classpath.

At the moment, to contribute properties from a common library, you should use an EnvironmentPostProcessor. #24688 is tracking making this easier.

[membersound]

EnvironmentPostProcessor works for the moment, thnx.