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.

We discuss how to work with directories, sub-directories, and traverse them using Java and the DirectoryStream method. Learn more.

Learn how to use synchronous and asynchronous callbacks in Java—including callbacks with lambda expressions, CompletableFuture, and more.

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 ...

How to write a Java palindrome program for Strings Good programmers need to create code that efficiently solves problems, using various methods. A popular academic exercise is to create a program that ...