OOPS (or object-oriented programming) is a programming style that considers everything in an application program to be an object. It simplifies programming. The primary oops notions are as follows:  Class - a collection of methods and variables. A class can be used by generating objects of the class.  Inheritance - we can build a parent class when there are common attributes that can be utilized. The child classes can then inherit the parent class's shared methods and variables. The Animal class is a popular example. If Dog and Lion are two distinct animals, they can inherit Animal's common methods such as run(), eat(), and makeSound().  Because the sounds of Dog and Lion differ, each will have its own implementation.  Polymorphism is the process of redefining how something works by employing a new implementation. Overloading and overriding can be used to produce polymorphism.  Abstraction - In sophisticated real-time applications, not all details must be displayed to the user. We can isolate what an item does from how it works via abstraction and display the user merely the 'what'.  Encapsulation - Encapsulation is the notion of combining data and code into a single unit in order to conceal the underlying workings of the code from an end-user. A class, for example, encompasses multiple member variables and methods that may be inaccessible from outside the class.  In addition, the interviewer may ask you to describe any or all of these.  You only need to describe the fundamental notion for any Infosys android developer interview questions.