Packages in Java

We have already encountered the concept of packages when we were learning about importing different libraries. Packages are the same, but now we will create them ourselves.

I have a class called "Dog" and a Main class. Earlier, we created these classes in the same file, but now we can do it nicely. I have split these classes into two different files. One file contains the "Dog" class, and the other contains the main class. Also, it's worth noting that the "Dog" class is located in the "animals" package.

Auto overriding

Here, it is worth reminding about a very useful IntelliJ feature. We can automatically generate various pieces of repetitive code. These could be:

• constructors;
• getters;
• setters;
• toString() methods, and so on.

In our case, we want to generate the toString() method. To do this, press the appropriate key combination:

• For Mac - Command + N;
• For Windows - Alt + Insert.

This will open a window with options. Choose the code generation option we want using the arrow keys and press Enter. Next, it will prompt us to choose how many fields we want to generate the toString() method. Choose all fields and click OK.

The toString() method will be automatically generated and ready to use!

How to import a package?

Let's go back to packages. We have already generated our Dog class. Now, we need to create an object of this class and call its method in the Main class. To do this, we need to import the Dog class from the animals package, but IntelliJ will do this for us. Next, our task is to create an object of the Dog class using the constructor:

Great, we have successfully created an object of the Dog class and printed information about it to the console using the overridden toString() method.

How to create packages and classes inside

Now, let's understand how to create packages and classes within packages. To do this, we will create a package called birds inside the animals package and create a class called Parrot within it:

• Right-click on the src folder and select "Package" from the pop-up list. Enter the name of the package and click "Create":

• Now, with the birds package created, we can create a class inside it. Right-click on the birds package and select "Class." Give the class a name, in our case, Parrot, and click "Create":

Note

There's no need to be afraid of the extensive array of features you see when creating something. You won't have to use all of them right away (even I don't use them very often). With experience, you'll become familiar with most of these features, and I'll cover most of them in this course.