We all are using private methods in our classes. There are two different ways to use them – one is good and valid while the second one is a hint that something can be wrong with our design.
In the object-oriented world, each developer who wants to live long and prosper should know the SOLID rules. SOLID is just an acronym of basic tips for writing maintainable, readable code. We all know many developers who follow these rules. And we all know many who know them, but don’t use them. And finally, plenty of programmers have heard something about SOLID, but don’t bother to learn anything about it. However well we use it, we can agree that sticking to SOLID is a good practice. But there are always compromises.
Before Java8 if we wanted to check if something is not null, we had to write crappy null checks. Today we have better alternatives.