How can I use the inner class? I didn't get it right

Question

More explain

Answer 1

In Java, just like methods, variables of a class too can have another class as its member. Writing a class within another is allowed in Java. The class written within is called the nested class, and the class that holds the inner class is called the outer class.

Answer 2

class Outer_Demo {
class Nested_Demo { }
}