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.

There are over 40 functional interfaces listed in the java.util.functions package, which can make the prospect of functional programming in Java ... This restriction doesn’t apply to the Function ...

Close your Closeable JDBC resources. Both the JDBC Statement and Connection objects implement the Closeable interface, which means we should invoke the close() method on them when they are no longer ...

The AI-powered code-completion tool, unveiled years ago as an "AI pair programmer," can now rewrite your Java code in Microsoft's open-source-based, cross-platform code editor, thanks to an update of ...

For an introduction to Java interfaces, including the difference between classes and interfaces, see my Java 101 tutorial Working with interfaces in Java. Nesting interfaces in classes.