What is interfaces?

Answer 1

Interfaces are a way to define exactly what methods should be used for a program. It creates a template for other programmers to follow. If functions are not made in a program that are listed in the interface, the compiler will complain. It forces compliance to an expected standard.

It's useful to design it early on in development. The interface functions should convey to programmers the meaning of what the function will do with appropriate naming. The programmers can then make code in any way to suit the interface functions intended design.

Answer 2

interfaces in java are part of java APIs I.e it is a way of a programming language to interact with user

Answer 3

it is a collection of abstract methods abstract methods don't have body where they are declared body of abstract method is provided by the class which implement them

Answer 4

The way of a system to interact with user is called interaction.
There are 2 types of interface they are cui(command user interface) and gui(graphics user interface).