Solve the problem of No active profile set, falling back to 1 default profile: “default” and how to check the spring boot version number

1. Question

Today, when starting the project, the following error occurred:

That is No active profile set, falling back to 1 default profile: "default".

This problem is not an error because its log level is info (log.level = info), but what does the above mean in English? Translated into Chinese is: 未设置激活的配置文件，回退到 1 个默认配置文件：“默认”.

When we use multiple configuration files, for example application-dev.yml, application-prd.ymlfiles, as shown in the figure below: