A public method should never be called by another public method within the same class hierarchy. It should only be called by other classes via the classes' public interface. Class calls might not be ...

A method might accept a specific type and its subclasses, but you want to restrict usage to a select few implementations of your own design. Java's open inheritance model can feel like an open ...

This method makes it possible to sort an array of unsorted constants. getDeclaringClass() returns the java.lang.Class object corresponding to the current constant’s enum.

Abstract classes and interfaces in Java serve fundamentally different purposes. Learn the differences between these Java language elements and how to use them in your programs.