What is the purpose of static inner class in Java?

Static Nested Classes As with class methods and variables, a static nested class is associated with its outer class. And like static class methods, a static nested class cannot refer directly to instance variables or methods defined in its enclosing class: it can use them only through an object reference.

Why do inner classes have to be static?

The static inner class can access the static members of the outer class directly. Nested static class doesn’t need a reference of Outer class but a nonstatic nested class or Inner class requires Outer class reference. A non-static nested class has full access to the members of the class within which it is nested.

Why Java requires inner class What do you understand by static inner classes in Java and where will you use a static and non-static class?

Uses static keyword so it means it is static member of the outer class and can be accessed like that. Inner class needs an instance of outer class for initialization whereas static nested class does not need an instance of outer class as it is associated to the whole class and not to an instance.

Should nested classes be static?

A nested class could be nonstatic or static and in each case is a class defined within another class. A nested class should exist only to serve is enclosing class, if a nested class is useful by other classes (not only the enclosing), should be declared as a top level class.

Can Java class be static?

The answer is YES, we can have static class in java. In java, we have static instance variables as well as static methods and also static block. Classes can also be made static in Java.

What are the advantages of inner classes?

The main advantages of a nested (inner) class are:

  • It shows a special type of relationship, in other words, it has the ability to access all the data members (data members and methods) of the main class including private.
  • They provide easier code because it logically groups classes in only one place.

When should a class be static?

Use a static class as a unit of organization for methods not associated with particular objects. Also, a static class can make your implementation simpler and faster because you do not have to create an object in order to call its methods.

What are the types of inner classes?

There are four types of inner classes: member, static member, local, and anonymous.

  • A member class is defined at the top level of the class.
  • A static member class is defined like a member class, but with the keyword static.
  • A local inner class is defined within a method, and the usual scope rules apply to it.

Can a outer class be static?

We can’t declare outer (top level) class as static because the static keyword is meant for providing memory and executing logic without creating Objects, a class does not have a value logic directly, so the static keyword is not allowed for outer class.