Inheritance: When object of one class(subclass/child class) access all the properties and behavior of another class(parent class) is known as Inheritance. Abstract: In java abstract means to show only main functionality to user and hide the complex coding behind that,this can be partially achieve by using Abstract class and fully achieved with the help of Interface. Static: Static i s used to make program memory efficient,it allocate memory only in the class area .There is no need to create instance(object) of that class to call its method.