What concepts come under Polymorphism in java?

Polymorphism in Java is a concept by which we can perform a single action in different ways. Polymorphism is derived from 2 Greek words: poly and morphs. The word "poly" means many and "morphs" means forms. So polymorphism means many forms.

There are two types of polymorphism in Java: compile-time polymorphism and runtime polymorphism. We can perform polymorphism in java by method overloading and method overriding.

1. Compile-time Polymorphism (Static Polymorphism): In Java, we can achieve compile-time polymorphism through method overloading. Method Overloading allows different methods to have the same name, but different signatures where the signature can differ by the number of input parameters or type of input parameters or both.

2. Runtime Polymorphism (Dynamic Polymorphism): In Java, we can achieve runtime polymorphism through method overriding. If a subclass provides a specific implementation of a method that is already provided by its parent class, it is known as Method Overriding. It is used for Code Reusability and Method Overriding.

In addition to these, Java also has Interface which is another way to achieve Polymorphism. An interface is a completely "abstract class" that is used to group related methods with empty bodies. To access the interface methods, the interface must be "implemented" (kinda like inherited) by another class with the implements keyword (instead of extends). The body of the interface method is provided by the "implement" class.