Private Methods Over Public Methods

Question

I was examining the StringTokenizer.java class and there were a few questions that came to mind.

I noticed that the public methods which are to be used

Answer 1

Public methods are generally code that other classes which implement that class will want to use. Private methods are generally not as useful outside the class, or don't(alone) serve the purpose of what the class is meant to accomplish.

Say you're in your IDE of choice, and you implement a some class A. Class A is only designed to do one thing, say document generation. Naturally you will have some mathematical and byte operation methods in Class A that are required to do document generation, but people trying to use Class A are not going to need these other methods, because they just want a document. So we make these methods private to keep things simple for any future users of our class.