https://github.com/spring-projects/spring-boot/tree/main/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition

@ConditionalOnProperty("...")
@ConditionalOnBean(SomeBean.class)
    https://docs.spring.io/spring-boot/api/java/org/springframework/boot/autoconfigure/condition/ConditionalOnBean.html

baeldung
https://www.baeldung.com/spring-conditionalonthreading
2019
https://reflectoring.io/spring-boot-conditionals/
https://habr.com/ru/articles/462541/