What is the purpose of Java interface variables?

The purpose of Java interface variables is to define the specifications of a variable and indicate that an object possesses the characteristics of a particular interface. Interface variables can hold any object that implements the interface but can only access the object’s methods and attributes through the interface. By using interface variables, it is possible to reference and manipulate objects of different classes in the code, enabling polymorphism and flexibility. Additionally, interface variables can be utilized for implementing features such as callback mechanisms and event handling.