In this Java 101 tutorial, I’ve explained how interfaces differ from classes, and showed you how to declare, implement, and extend interfaces in your Java programs.

When to use interfaces in Java. Interfaces are very useful for decoupling code and implementing polymorphism.We can see an example in the JDK, with the List interface: ...

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 ...