Java polymorphism and its types

Polymorphism in Java allows entities to take different forms, enhancing code maintainability. Java supports four types of polymorphism: coercion, overloading, parametric, and subtype. Subtype polymorphism involves upcasting and late binding to execute various versions of a superclass method. Abstract classes and methods define more generic class hierarchies, while downcasting reverts to subtype-specific functionalities. Runtime type identification (RTTI) ensures casting safety, and covariant return types enhance method return flexibility.