Interface is a set of abstract methods. A class in Java implements an interface and inherits the abstract methods of the interface. It is not a class. Writing an interface is the same as writing a class. A class tells us about the attributes and behaviors of an object. An interface contains behaviors that a class implements.

Class is a template/blueprint that describes the behavior that an object supports.

Exception is a problem that arises during the execution of a program.

Here is the list of some packages to be used in Java code: