Nested Classes

A Nested Class is a class that is defined within another class. In Java, nested classes can be categorized into several types, such as static nested classes, inner classes, local classes, and anonymous classes.

Types of Nested Classes:

  1. Static Nested Class: A nested class that is declared static. It can access the static members of the outer class but cannot access the non-static members.
    • Example:
    class Outer {
    static int num = 10;
    static class Inner {
        void display() {
            System.out.println(num);
        }
    }
}


2. **Inner Class (Non-static Nested Class)**: A class that is defined inside another class without the `static` keyword. It can access both static and non-static members of the outer class.

   * Example:

   ```java
   class Outer {
       int num = 10;
       class Inner {
           void display() {
               System.out.println(num);
           }
       }
   }

  1. Local Inner Class: A class defined inside a method. It can access the local variables and parameters of the method.

    • Example:
    class Outer {
    void method() {
        class Inner {
            void display() {
                System.out.println("Inside method");
            }
        }
        Inner inner = new Inner();
        inner.display();
    }
}

  2. Anonymous Inner Class: A class without a name, defined at the time of instantiation. It’s often used in event handling.

    • Example:
    class Outer {
    void method() {
        Runnable r = new Runnable() {
            @Override
            public void run() {
                System.out.println("Anonymous class");
            }
        };
        r.run();
    }
}

🔗 Related Notes