Fundamentals Of Object-Oriented Programming: Java and IntelliJ - Interfaces

The video tutorial explains the concept of interfaces in programming, highlighting their role as reference types that can contain constants, methods, and nested types. It demonstrates how interfaces, like abstract classes, cannot be instantiated but can be implemented by other classes. Using a UML model, the tutorial shows how a Person and a Dog class implement a Walkable interface, sharing common features like walking. The tutorial then guides through coding the Walkable interface in Intellij, implementing the walk method in both classes, and testing the implementation in a main program. It emphasizes the importance of using interfaces for efficient, reusable code.

What can an interface in Java contain?

• Only nested types

• Only methods

• Constants, methods, signatures, default methods, static methods, and nested types

• Only constants and methods

Why can't interfaces be instantiated?

• Because they only contain method signatures

• Because they do not have constructors

• Because they are reference types

• Because they are abstract classes

In the UML model example, which classes implement the Walkable interface?

• Person and Dog

• Animal and Person

• Dog and Cat

• Person and Cat

What is a good practice when naming interfaces?

• Use adverbs

• Use adjectives

• Use verbs

• Use nouns

What keyword is used to implement an interface in a class?

• extends

• implements

• inherits

• uses

What is the benefit of using interfaces for common features across classes?

• It reduces the need for classes

• It allows for code reuse and efficient design

• It makes the code more complex

• It eliminates the need for methods

What happens when you call the walk method on a Person object?

• It throws an error

• It does nothing

• It prints 'Dog is walking'

• It prints 'Person is walking'