Access control and offering a sound interface.
You don’t need getters and setters if every attribute is public, but you might want to make sure attributes are accessed in a specific way or a change to an object has to trigger something, or the change has to wait until the object is done with something. Java just has tools to enforce a user of your objects to access its attributes through the methods you designed for that. It’s a safeguard against unintended side effects, to only open up inner workings of a class as littles as necessary.
In a language without something like private attributes you’d have to account for far more ways someone might mutate the state of objects created by your code, it opens you up to far more possible mistakes.
I’m totally aware of the benefits of encapsulation, but the way java does it seems so unnecessarily boilerplatey (C# is better, functional programming makes encapsulation even simpler, but that’s a different paradigm…)
I like how Rust approaches this via the module system and crates (you have pub for the public interface, pub(crate) for crate/lib wide access and no modifier for being only allowed to access in the current module and submodules of that module)
