Java Inner Classes: Types & Usage Guide

In Java, an inner class is a class defined within another class. There are four types of inner classes.

1. Static Nested Class: A static nested class is an inner class defined with the static modifier, which can be accessed directly using the outer class’s name without the need for an instance of the outer class.
2. Member Inner Class: A member inner class is a non-static class defined within an outer class that can access the outer class’s member variables and methods.
3. Local Inner Class is a class defined inside a method and can only be accessed within that method.
4. Anonymous inner class is an inner class without a name, commonly used to implement interfaces or extend parent classes, and can only create objects at the point of declaration.

To properly define an inner class in Java, you can follow these steps:

1. Define the type of inner class within the outer class (static, member, local, anonymous).
2. Based on the type of inner class, determine the access modifier and location of the inner class.
3. In the outer class, reference the inner class by its type and name.
4. In an inner class, you are able to access the member variables and methods of the outer class.

By following the above steps, you can accurately define Java inner classes and use them to implement specific functionality in your code.