See the Java 101 Java interfaces tutorial for a more in-depth introduction to using interfaces in your Java programs, including where and where not to use default, static, and private methods.

What is an Abstract Class? An abstract class is a class that is declared abstract —it may or may not include abstract methods. Abstract classes cannot be instantiated, but they can be subclassed. An ...

We use interfaces to add certain behavioral functionality that can be used by unrelated classes. For instance, Comparable, Comparator, and Cloneable are Java interfaces that can be implemented by ...

In addition to writing for JavaWorld, he has written his own Java book for beginners— Java 2 by Example, Second Edition (Que Publishing, 2001; ISBN: 0789725932)—and helped write Using Java 2 ...

In Java SE, mark a class or interface as 'final' if you want to stop it from being changed or extended. Use it when you're sure no one should make subclasses or implementations.

Sample Consumer interface use cases. The functional Consumer interface is used extensively across the Java API, with a number of classes in the java.util.function package, such as ObjIntConsumer, ...

Java Supplier interface tutorial. As you can see, the code for the class that implements Java’s Supplier interface is fairly simple. The only requirements are the class declaration and the ...

Java Coding Samples. Various Java programs to illustrate various concepts. A Hello World! Java program. Calling Methods. A sample of how to call methods in the same class. For loop. A simple example ...