What is the rule of the class in Java?

It can access any private instance variable of the outer class . Like any other instance variable, we can have access modifier private, protected, public, and default modifier. Like class, an interface can also be nested and can have access specifiers.24 Şub 2022

Rules for Java Class A class can have only public or default(no modifier) access specifier . It can be either abstract, final or concrete (normal class). It must have the class keyword, and class must be followed by a legal identifier. It may optionally extend only one parent class.

You can observe the constructor chain for the inner class when you extend an inner class . so you can see that you are able to call the super constructor of your nested class passing to that constructor the MainClass , and calling . super on mainClass object instance.