In Spring Boot, application.properties is the default file from which configuration values are picked up. Spring Boot can pick the application.properties file from anywhere on the classpath. Typically, application.properties is located at srcmain esources, as shown in the following screenshot:

The following snippet shows how you can customize Spring Security using the configuration in application.properties:

    security.basic.enabled=false
    management.security.enabled=false
    security.user.name=user-name
    security.user.password=user-password
    security.oauth2.client.clientId: clientId
    security.oauth2.client.clientSecret: clientSecret
    security.oauth2.client.authorized-grant-types:                
    authorization_code,refresh_token,password
    security.oauth2.client.scope: openid

Similar to these, other Spring Boot starters, modules, and frameworks can be customized through configuration in application.properties.

In the next section, we'll look at some of the configuration options Spring Boot provides for these frameworks.