Cursos /

Java OOP

1. How to Work With IDE?

Installing IntelliJ IDEA (MacOS)

Installing IntelliJ IDEA (Windows)

Code Editor Main Features

Debugger

Packages

How to do Tasks?

2. OOP

Finally, we can start learning Object-Oriented Programming (OOP) in Java. It will be challenging, but I'm confident that you'll succeed! In this section, we'll cover all the principles of OOP, explain why OOP is important. You'll learn how to inherit classes, overload and override methods, encapsulate data from other classes, and work with abstraction. Moreover, you'll reinforce all these theoretical concepts with practical exercises, working on assignments in your IDE. You'll gain a wealth of knowledge, both practical and theoretical, so let's get started!

What is OOP?

OOP Principles: Inheritance

Challenge: Inheritance

OOP Principles: Polymorphism

Challenge: Polymorphism

OOP Principles: Encapsulation

OOP Principles: Abstraction

Challenge: Abstraction

3. Interface

In the previous section, we concluded that all Object-Oriented Programming is mainly built on abstraction. However, an abstract class has one significant limitation – you can inherit from only one abstract class. But what if we need more? Interfaces come to the rescue. In this section, you will learn what an interface is, why it's necessary, how to use it correctly, and you will continue practicing Object-Oriented Programming. Let's turn you into a professional!

What is Interface?

Challenge: Interface

Abstract Class vs Interface

Default Methods

Static Methods

Summary

Challenge: Polymorphism

Task

You are given a Parent class and a Child class that inherits from the Parent class. Your task is to override the parent method named method in the Child class so that it returns "This is the overridden method!".

Next, you need to overload this method by adding a parameter int parameter so that the method returns: "This is the overloaded method with int parameter: " + parameter.

Note that the methods should return these values, not display them on the screen!

Feel free to use the "Hint" and "Solution" buttons if you have difficulties understanding the task.

Link to the task: GitHub

Warning

Please do not modify the Parent class!

Open the src folder, then open the main/java/codefinity package.

There will be Parent and Child classes, open the Child class.

Use the @Override.

Use syntax: return "This is the overridden method!"; for the first method.

Overload this method by adding int parameter to the new one.

Use syntax

return "This is the overloaded method with int parameter: " +
      parameter.

for the second method;

Run tests by pressing the "Run Code" button.

Tudo estava claro?

Seção 2. Capítulo 5

Challenge: Polymorphism

Task

Next, you need to overload this method by adding a parameter int parameter so that the method returns: "This is the overloaded method with int parameter: " + parameter.

Note that the methods should return these values, not display them on the screen!

Feel free to use the "Hint" and "Solution" buttons if you have difficulties understanding the task.

Link to the task: GitHub

Warning

Please do not modify the Parent class!

Open the src folder, then open the main/java/codefinity package.

There will be Parent and Child classes, open the Child class.

Use the @Override.

Use syntax: return "This is the overridden method!"; for the first method.

Overload this method by adding int parameter to the new one.

Use syntax

return "This is the overloaded method with int parameter: " +
      parameter.

for the second method;

Run tests by pressing the "Run Code" button.

Tudo estava claro?

Seção 2. Capítulo 5