The Java programming language allows you to define a class within another class. … Non-static nested classes (inner classes) have access to other members of the enclosing class, even if they are declared private. Static nested classes do not have access to other members of the enclosing class.
Why do we need static inner class?
Use a non-static nested class (or inner class) if you require access to an enclosing instance’s non-public fields and methods. Use a static nested class if you don’t require this access.
Should static classes be inner?
An inner class, by default, has an implicit reference to an object of the outer class. If you instantiate an object of this from the code of the outer class, this is all done for you. … As a basic rule, if the inner class has no reason to access the outer one, you should make it static by default.
What is the use of static nested class?
Java static nested class
A static class is a class that is created inside a class, is called a static nested class in Java. It cannot access non-static data members and methods. It can be accessed by outer class name. It can access static data members of the outer class, including private.
What is the difference between inner class and static inner class?
1) First and most important difference between Inner class and nested static class is that Inner class require instance of outer class for initialization and they are always associated with instance of enclosing class. On the other hand nested static class is not associated with any instance of enclosing class.
What is the difference between a static and non-static inner class?
A non-static nested class has full access to the members of the class within which it is nested. A static nested class does not have a reference to a nesting instance, so a static nested class cannot invoke non-static methods or access non-static fields of an instance of the class within which it is nested.
Can Java inner class be static?
As with instance methods and variables, an inner class is associated with an instance of its enclosing class and has direct access to that object’s methods and fields. Also, because an inner class is associated with an instance, it cannot define any static members itself.
What is a static inner class?
In Java a static nested class is essentially a normal class that has just been nested inside another class. Being static, a static nested class can only access instance variables of the enclosing class via a reference to an instance of the enclosing class.
Why can’t inner classes have static members?
The reason why inner classes cannot have static members is because static members are usually instantiated when the program starts. However, an inner class depends on having an instance of its enclosing class in order to create it and then access it’s members.
Which is the scope of a class nested inside another class?
A class can be declared within the scope of another class. Such a class is called a “nested class.” Nested classes are considered to be within the scope of the enclosing class and are available for use within that scope.