Override a single property in a parent project of a application.properties defined in child project?

Question

I have a project, let's call it BaseProject, which contains a properties file defining different configurations. One of those properties could be security.password.minlength=4.

Now I have a ProjectA which builds up on BaseProject and there for depends on it.

ProjectA
   |
   |--BaseProject

Now in ProjectA I would like to have a default security.password.minlength of 8.

If I simply add a application.properties file to my ProjectA, containing security.password.minlength=8 and the specific property is set to 8. Al tough all the other properties form my BaseProject are ignored now, giving me the exception: java.lang.IllegalArgumentException: Could not resolve placeholder

I still would like to use all properties defined in BaseProject but solely set the security.password.minlength to a different value. How can I achieve this?

Update

Currently I let Spring do the handling of the application.properties file. Inside my application, I simply get the values from the Spring environment.

Answer 1

I found the following solution for me:

BaseProject has a application.properties which contains all the default values.

ProjectA has a projectA.properties which is I integrate with

@PropertySource("projectA.properties")
public class ProjectA {

    public static void main(String[] args) {
    SpringApplication.run(ProjectA .class, args);
    }
}

This allows me to override any property from the BaseProject project in the projectA.properties file. The properties which I don't define in projectA.properties are still taken from the application.properties of the BaseProject`.