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

The only reason I could think of why private methods are useful is because it helps you from writing duplicate code.

In addition to consolidating duplicate code (often expressed as "Don't Repeat Yourself" or "DRY"), use of private methods can also help you to structure and document your code. If you find yourself writing method which does several things, you may wish to consider splitting it into several private methods. Doing so may make it clearer what the inputs and outputs for each piece of logic are (at a finer granularity). Additionally, descriptive method names can help supplement code documentation.