The object passed to addActionListener() is instantiated from an anonymous class that implements the java.awt.event.ActionListener interface. Nested interfaces and classes.

You’ll also understand why many Java developers have adopted lambda expressions and method references as a cleaner, simpler alternative to anonymous classes. Note that code examples in this ...

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 ...