Classes

Creating a Class

We’ve already been creating and using classes in our Java programs up to this point. This is because Java is a truly object-oriented language, meaning that all code in Java must be contained as part of a class.

Java requires that each class be stored in a file with the same name, followed by the .java file extension. By convention, class names in Java are written in CamelCase, meaning that each word is capitalized and there are no spaces between the words. We’ll follow these rules in our code.

So, to create a class named Student, we would place the following code in a file named Student.java:

public class Student{
  
}

As we’ve already learned, each class declaration in Java includes these parts:

1. public - this keyword is used to identify that the item after it should be publicly accessible to all other parts of the program. Later in this chapter, we’ll discuss other keywords that could be used here.
2. class - this keyword says that we are declaring a new class.
3. Student - this is an identifier that gives us the name of the class we are declaring.

Following the declaration, we see a set of curly braces {}, inside of which will be all of the fields and methods stored in this class.

To follow along, create or open these three files: Student.java, Teacher.java, and Main.java. Let’s go ahead and add the class declaration code to each file.