Spring boot - how does it start?

Question

Java

Good evening.
I ask for advice.
There is an application that reads files from the file system and loads part of the content into the database. There are service classes, they have a number of methods, but the return types in the methods are repeated.
I would like to do it without a spring shell, without commands in the main.
The question is - how does the spring understand what exactly to do - where to start and how to finish? Is this possible without a clear chain of return types?

Answer 1

There is an application that reads files from the file system and loads part of the content into the database.

Well, in this case, to import the database, you need to use sql scripts and some kind of lib. For example flyway.

There are service classes, they have a number of methods, but the return types in the methods are repeated.

If necessary, generics can be used.

I would like to do it without a spring shell, without commands in the main.

In theory, flyway (or, for example, liquibase) are better suited for these purposes.