Hello, learner! In today's exciting chapter, we will unravel Polymorphism, a prominent feature of Object-Oriented Programming (OOP). Specifically, we will study its role in maintaining backward compatibility while introducing new features. Think of it as a software update that introduces new functions without breaking the older functionality — ingenious, isn't it?

Polymorphism, a principle that derives from the Greek words 'poly' (many) and 'morphism' (forms), enables a variable or method to assume multiple roles — to embody various behaviors or functions determined by its data type or class.

Consider a class Bird with a method canFly(). If we create subclasses like Sparrow, Penguin, and Ostrich, we can override the canFly() method for certain subclasses. This demonstrates polymorphism in action.

The Bird example demonstrates runtime polymorphism, where the method behaves differently depending on the object type ( or ). The superclass Bird provides a default implementation of as . This acts as a generic behavior for birds when no specific information is available. Subclasses override this method to provide species-specific behaviors. For example, the class overrides to return , while the class returns . This ability to modify behavior while maintaining a shared interface () is the essence of polymorphism.