Annotations Overview
By the end of this lesson, you'll be able to:
- Explain what an annotation is: metadata attached to a class or method
- Recognize @isTest and @AuraEnabled as two annotations you'll meet soon
- Distinguish an annotation from a regular keyword
Prerequisites: "Keywords Tour"
What an annotation looks like
@isTest
private class CalculatorTest {
@isTest
static void testAddition() {
System.assertEquals(4, 2 + 2);
}
}@isTest above the class tells Salesforce "this entire class exists only to run tests — don't count it toward certain limits, and don't deploy it as regular application logic." The annotation itself runs no code; it's an instruction about the code beneath it.
Annotation vs keyword
A keyword like public or static is part of the core language grammar — every Apex compiler must understand it to compile the class at all. An annotation like @isTest is metadata layered on top — it changes how Salesforce's platform treats the code (testing rules, API exposure, scheduling), not the fundamental meaning of the Apex statements themselves.
A few you'll meet in later modules
@isTest— marks a class or method as test-only code (a later Testing module goes deep on this).@AuraEnabled— exposes a method so a Lightning Web Component can call it (covered in the LWC module).@future— marks a method to run asynchronously, later, outside the current transaction (covered in the Asynchronous Apex module).
You don't need to use any of these yet — recognizing the shape (@SomeName above a class or method) is the goal of this lesson.
Exercise
As a comment, explain in your own words what makes an annotation different from a keyword like public.
Show hint
Think about what each one actually controls.
Annotations Overview Quiz
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Summary
An annotation is a piece of metadata attached above a class or method using @ — it doesn't change what the code does directly, but tells Salesforce (or a tool) something important about how to treat it.