Why we use inner classes in Java?

Inner classes are a security mechanism in Java. We know a class cannot be associated with the access modifier private, but if we have the class as a member of other class, then the inner class can be made private. And this is also used to access the private members of a class.

Why might you declare an inner class?

When should we use nested class in Java?

As mentioned in the section Nested Classes, nested classes enable you to logically group classes that are only used in one place, increase the use of encapsulation, and create more readable and maintainable code.

What is the difference between an inner class and a sub class?

inner classes are in the same file, whereas subclasses can be in another file, maybe in another package. You cannot get an instance of an inner class without an instance of the class that contains it. inner classes have the methods they want, whereas subclasses have the methods of their parent class.

Are inner classes bad?

Inner classes are frequently used, and something very similar – anonymous classes – are practically indispensable, as they are the closest thing Java has to closures. So if you can’t remember where you heard that inner classes are bad, try to forget about it! They’re not “bad” as such.

What is the difference between inner class and anonymous class in Java?

A local inner class consists of a class declared within a method, whereas an anonymous class is declared when an instance is created. So the anonymous class is created on the fly or during program execution.

How many inner classes a class can have in Java?

There are basically four types of inner classes in java. Nested Inner class can access any private instance variable of outer class. Like any other instance variable, we can have access modifier private, protected, public and default modifier. Like class, interface can also be nested and can have access specifiers.

Are inner classes commonly used in Java?

An inner class in a Java program is nothing but the class that is declared and used in an already functioning class , so as to use all the functions and members which are accessible to the outer class. This is typically used when the coding pattern in the program needs to be more organized while reducing the length of the code.

What are inner classes in Java?

Java Inner classes are class within Class. Inner class instance has special relationship with Outer class. This special relationship gives inner class access to member of outer class as if they are the part of outer class.

What is difference between nested and inner class in Java?

In Java, a nested class that is not static is called an inner class. An inner class can interact with the instance of its enclosing class—it has access to private variables and methods of the enclosing class. An inner class, being ‘bound’ to an enclosing instance, cannot declare static members of its own.