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 ...

Classes, fields, methods, constructors, and objects are the building blocks of object-based Java applications. This Java tutorial teaches you how to declare classes, describe attributes via fields, ...

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 and ...

Java's default constructor allows developers to create instances of classes when no other constructors are explicitly defined. The default constructor in Java takes no arguments -- it simply ...

Separating localized resources from the source code where they are used is a well-known and approved design. Java's ResourceBundle class from the java.util package provides a straightforward way to ...