One of the questions I get from admins starting to write Apex is: What’s the difference between a class, a method, and a sub-class? It’s an important distinction that’s easy to miss when you're focused on just getting the code to work.
Here’s the breakdown:
A Class is the container. Think of it like a toolbox. It can hold properties (data) and methods (actions).
A Method is an action the class can perform. It’s like a tool in the box—each method does something specific.
A Sub-Class is a class defined inside another class. It’s used for organizing related logic or creating structured data objects within a class.
For example:
public class ReservationUtils {
public class ReservationData {
public String name;
public Date reservationDate;
}
public static String formatReservation(ReservationData res) {
return res.name + ' - ' + res.reservationDate.format();
}
}
In this example:
ReservationUtils is the class
ReservationData is a sub-class used for structure
formatReservation() is a method that performs an action
Keeping these roles clear makes your Apex code easier to read, maintain, and test. It also sets you up for more modular, reusable development.
