Sealed classes in Java let developers limit the creation and use of subclasses and preserve the class hierarchy. Here is how sealed classes in Java work.

Here's how to make classes, fields, methods, constructors, and objects work together in your Java programs.

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.

He has led software development projects to build enterprise-class software applications and has extensive experience with Java and Perl. He is the author of several Java books, including one called ...