There are some advantages
- Java is type safe. Compiler will report issues if you are
configuring right bean class qualifiers. - XML based on configuration can quickly grow big. [Yes we can split
and import but still] - Search is much simpler, refactoring will be bliss. Finding a bean
definition will be far easier.
There are still people who like XML configuration and continue to do it.
References:
Java configuration advantages
Some more reasons