Starting with JDK 1.1, Java provided the ability to create nested classes. A nested class is defined inside another class. There are two types of nested classes: static nested classes and inner ...

Historically, Sun tried very hard to avoid such changes: Java 1.1 introduced inner classes, Java 1.4 introduced “assert”, and beyond that the language was the same language we’d been using ...

If the thing inside the parentheses is also a class, it becomes an inner class. Java has supported inner classes since version 1.1.