Springboot not loading application.dev.properties file

Try adding a vm argument in the run configuration:

-Dspring.profiles.active=dev

A few issues I noticed:

1. @Value property name should be a String like @Value("${server.database.host}")
2. Profile specific property files should follow application-{profile}.properties format, e.g. application-dev.properties
3. Try passing the profile with -D like java -Dspring.profiles.active=dev -jar app.jar

You are supposed to specify which profile to run with as follows:

mvn spring-boot:run -Dspring-boot.run.profiles=foo,bar

Also see documentation: https://docs.spring.io/spring-boot/docs/current/maven-plugin/examples/run-profiles.html

If running on Eclipse or STS, then use following steps:

1. Right click on project -> Run As -> Run Configuration.

2. In the new window, select spring boot application on left side, and add details on the right and in the profile dropdown, select dev.

3. Click apply and run.