The biggest problem addressed here is one where an EnvironmentPostProcessor (reasonably) adds entries to the defaultProperties in the bootstrap context, but then that property source is not merged with the parent, or is merged too late (because it only happens when the application context parent is set). The result would be that things that were activated during bootstrap would be not be activated in the main context, or would be activated too late (early enough for beans to bind to but not for other listeners and post processors to get access to the additional properties). See https://github.com/spring-cloud/spring-cloud-sleuth/issues/126
Spring Cloud Context
Utilities and special services for the ApplicationContext of a Spring Cloud application (bootstrap context, encryption, refresh scope and environment endpoints).