The "[Customize the Environment or ApplicationContext Before It Starts](https://docs.spring.io/spring-boot/how-to/application.html#howto.application.customize-the-environment-or-application-context)" section in the documentation links to deprecated Javadoc and also describes the deprecated `META-INF/spring.factories` file, such as: ``` org.springframework.boot.env.EnvironmentPostProcessor=com.example.YourEnvironmentPostProcessor ``` <!-- Thanks for raising a Spring Boot issue. Please take the time to review the following categories as some of them do not apply here. 🙅 "Please DO NOT Raise an Issue" Cases - Question STOP!! Please ask questions about how to use something, or to understand why something isn't working as you expect it to, on Stack Overflow using the spring-boot tag. - Security Vulnerability STOP!! Please don't raise security vulnerabilities here. Head over to https://spring.io/security-policy to learn how to disclose them responsibly. - Managed Dependency Upgrade You DO NOT need to raise an issue for a managed dependency version upgrade as there's a semi-automatic process for checking managed dependencies for new versions before a release. BUT pull requests for upgrades that are more involved than just a version property change are still most welcome. - With an Immediate Pull Request An issue will be closed as a duplicate of the immediate pull request, so you don't have to raise an issue if you plan to create a pull request immediately. 🐞 Bug report (please don't include this emoji/text, just add your details) Please provide details of the problem, including the version of Spring Boot that you are using. If possible, please provide a test case or sample application that reproduces the problem. This makes it much easier for us to diagnose the problem and to verify that we have fixed it. 🎁 Enhancement (please don't include this emoji/text, just add your details) Please start by describing the problem that you are trying to solve. There may already be a solution, or there may be a way to solve it that you hadn't considered. TIP: You can always edit your issue if it isn't formatted correctly. See https://guides.github.com/features/mastering-markdown -->