Spring MVC #Value/#ConfigurationProperties working on MainConfig but not on SecurityConfig - spring

Question

I have a simple Spring MVC 5 project, with security layer enabled. Everything works good except the properties loading, only on Security Config.
I let you the scenario so you can see it.
application.properties (located at src/main/resources)
com.company.myapp.prop=myprop
MainConfig.java
#Configuration
public class MainConfig implements WebMvcConfigurer {
#Value("${com.company.myapp.prop}")
private String prop;
#Bean
public MySpecialBean mySpecialBean() {
System.out.println(prop); // output > myprop
return new MySpecialBean();
}
}
SecurityConfig.java
#Configuration
#EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {
#Value("${com.company.myapp.prop}")
private String prop;
#Bean
public MySpecialSecurityBean mySpecialSecurityBean() {
System.out.println(prop); // output > null
return new MySpecialSecurityBean();
}
}
I don't understand why it's happening. I already switched the #EnableWebSecurity annotation to the app class, try to set the PropertySourcesPlaceholderConfigurer myself, but nothing works.
Do you have any idea what's going on?

Answer 1

From official docs about #PropertySource:
Resolving ${...} placeholders in <bean> and #Value annotations
In order to resolve ${...} placeholders in definitions or #Value annotations using properties from a PropertySource, you must ensure that an appropriate embedded value resolver is registered in the BeanFactory used by the ApplicationContext. This happens automatically when using in XML. When using #Configuration classes this can be achieved by explicitly registering a PropertySourcesPlaceholderConfigurer via a static #Bean method. Note, however, that explicit registration of a PropertySourcesPlaceholderConfigurer via a static #Bean method is typically only required if you need to customize configuration such as the placeholder syntax, etc. See the "Working with externalized values" section of #Configuration's javadocs and "a note on BeanFactoryPostProcessor-returning #Bean methods" of #Bean's javadocs for details and examples.
You should try to add annotation #PropertySource into the your config class.
#Configuration
#PropertySource("classpath:my.properties")
public class MainConfig implements WebMvcConfigurer {}
and then try to access your property in SecurityConfig class
To get full information see official docs
I hope it will help you

Answer 2

This works for me.
I guess you have another class that triggers the application and that is annotated with #SpringBootApplication
Also, your methods mySpecialBean do not return a MySpecialBean instance, so this probably does not even compile.
Is there any other class that you are using? Please advice

Answer 3

Finally got it!
The problem was related with some dependency priorities and unnecessary beans declarations. Getting into details, I'm working with OAuht2 and I started with this tutorial. In the end I've made a mix with this one too (more recent). The problem was related with these #Bean's that don't really need to be declared as beans:
ClientRegistrationRepository
ClientRegistration
OAuth2AuthorizedClientService
Spring was calling these beans before any other configuration, so any properties was not loaded yet. Maybe changing the priority, dependence or even the order would resolve the issue, but as I was analysing the code I found that these methods are only used on security configuration and not really needed along any other part of the app. So I removed the #Bean declaration and all works nice now! At the time these methods are called inside security config the properties are already loaded.
Hope to help someone out there.