The first half of this introduction to Java inheritance teaches you how to use the extends keyword to derive a child class from a parent class, invoke parent class constructors and methods ...

If another developer attempts to extend your parent class and introduce a new object type, a once exhaustive evaluation becomes incomplete and ineffective. Java does enable the option to mark a class ...

The release of Java SE 15 in Sept 2020 will introduce "sealed classes" (JEP 360) as a preview feature. A sealed class is a class or interface which restricts which other classes or interfaces may ...

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. Abstract classes ...