I never understood this. DI is for deciding program behavior. That should be a user choice. I don't understand how final users are supposed to (1) write XML files instead of providing simple human readable CLI flags, (2) know the program internals and being able to type in fully qualified class names.

$ ./my-server -reporting=email

vs

setting com.mycompany.package.subpackage.di.providers.abstract.ReportingProvider to com.mycompany.package.subpackage.di.providers.impl.EmailReportingProviderImpl.

The whole DI is a wrong concept. Dependencies should be instantiated at top level (main function) and explicitly passed down the call graph as interface instances.

DI breaks the call graph with (configurable) side effects. If you pass down dependencies explicitly you don't even need mocking frameworks for testing.