Application.yml - bootstrap.yml - prioroty

bootstrap.yml is loaded before application.yml.

It is typically used for the following:

when using Spring Cloud Config Server, you should specify spring.application.name and
spring.cloud.config.server.git.uri inside bootstrap.yml
some encryption/decryption information
Technically, bootstrap.yml is loaded by a parent Spring ApplicationContext. That parent ApplicationContext is loaded before the one that uses application.yml.

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bootstrap.yml or bootstrap.properties

It's only used/needed if you're using Spring Cloud and your application's configuration is stored on a remote configuration server (e.g. Spring Cloud Config Server).

Note that the bootstrap.yml or bootstrap.properties can contain additional configuration (e.g. defaults) but generally you only need to put bootstrap config here.

Typically it contains two properties:

location of the configuration server (spring.cloud.config.uri)
name of the application (spring.application.name)
Upon startup, Spring Cloud makes an HTTP call to the config server with the name of the application and retrieves back that application's configuration.


application.yml or application.properties

Contains standard application configuration - typically default configuration since any configuration retrieved during the bootstrap process will override configuration defined here.


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same content placed in both files then

appliaction yaml file have the higher priority and ovveride the content of the bootstrap property