What are the alternatives to public fields?

Question

I am programming a game in java, and as the question title suggestions i am using public fields in my classes. (for the time being)

From what i have seen public fields a

Answer 1

Getters and setters are part of the public interface of your class. It's a contract between the class designer/developer and the users of that class. When you define getters and setters, you should be committed to maintain them in future versions.

Attributes should only correspond the implementation of a given version of the class. In this way, the class developer may unilaterally change the implementation, hence the field, without breaking his/her commitment to maintain the interfaces.

Here is an example. Consider a class called Point. If you decide that a Point has x and y public attributes, then you may never change this. In contrast, if you have get/set X/Y methods, subsequent versions of the class may use various internal representations: rectangular coordinates (x, y), but also polar (r, theta), etc. All this without modifying the public interface.