A class inside another class is called a Nested Class. In other words, as a class has member variables and member methods it can also have member classes.
Static is one of the non-access modifier which has a huge role in Java. It can be usedwith both variables and methods. It is used when we want some variable or method not to be a part of any specific objectof a class rather common for all objects of the class.
Objects are constructed. You can never make a new object without invoking a constructor (and not just theconstructor of the object’s actual class type, but also the constructor of each of its superclasses).
Reusing the same method name in the same class or subclass but with different arguments(and optionally, a different return type) is called Method Overloading in Java.
Reimplementing the inherited method from the parent class in the child class is called Overriding in Java.
Variables are devices that are used to store data, such as a number, or a string of character data so that we canmanipulate them later in our program. Variables can be broadly classified in to 4 types in Java: