Salesforce Apex Language Overview

Salesforce Apex is a strongly typed, object-oriented programming language designed specifically for the Salesforce Platform. It enables developers to build custom business logic, automate complex processes, integrate Salesforce with external systems, and develop applications that go beyond the capabilities of declarative tools such as Flows, Validation Rules, and Approval Processes.

If you've worked with Java before, Apex will feel familiar because it follows a similar syntax and object-oriented programming concepts. However, Apex is designed specifically for Salesforce and runs entirely on its secure, cloud-based, multitenant platform.

Whether you're creating a trigger that updates related records, building a REST API, or processing millions of records in the background, Apex provides the flexibility to develop scalable and reliable business solutions.

What is Salesforce Apex?

Think of Salesforce as a modern smart office building.

Using tools like Flow, Validation Rules, Formula Fields, and Approval Processes, you can automate many day-to-day tasks without writing code. These are called declarative tools.

However, some business requirements are too complex for click-based automation. For example, you might need to:

• Update multiple related objects within a single transaction.
• Perform complex calculations involving hundreds of records.
• Call an external ERP or payment gateway.
• Generate custom business rules based on multiple conditions.
• Process millions of records efficiently in the background.

This is where Apex becomes essential.

Apex gives developers complete control over business logic while still following Salesforce's security model and Governor Limits.

Quick Overview of Salesforce Apex

Why Do We Need Apex?

Salesforce follows a Clicks Before Code philosophy, encouraging developers to use declarative tools whenever possible. However, not every business requirement can be implemented using clicks alone.

When automation becomes more complex or requires advanced programming capabilities, Apex provides the flexibility needed to build scalable and maintainable solutions.

Salesforce Apex vs Declarative Development

Salesforce provides both declarative and programmatic development options. Choosing the right approach depends on the complexity of your business requirement.

Simple Apex Example

The following Apex class counts the number of Contacts related to each Account and stores the value in a custom field named Number_of_Contacts__c.

// Simple Apex Class: Count Contacts per Account
public class AccountProcessor {

    public static void countContacts(List accountIds) {

        // Fetch related contacts using a relationship query
        List accounts = [
            SELECT Id,
                   (SELECT Id FROM Contacts)
            FROM Account
            WHERE Id IN :accountIds
        ];

        for(Account acc : accounts) {
            acc.Number_of_Contacts__c = acc.Contacts.size();
        }

        update accounts;
    }
}

How This Code Works

Things to Consider Before Writing Apex

Writing Apex is not just about making the code work. Well-designed Apex should be efficient, scalable, secure, and easy to maintain. Following Salesforce development best practices from the beginning helps improve application performance, simplifies future enhancements, and reduces technical debt.

Before you start writing Apex code, take a moment to evaluate whether coding is truly required and how your solution will perform as data volume and business complexity increase.

Use Declarative Tools First

Salesforce follows a Clicks Before Code philosophy. Whenever possible, solve business requirements using declarative tools before considering Apex development.

Declarative solutions are generally easier to configure, maintain, troubleshoot, and enhance compared to custom code.

Before writing Apex, ask yourself whether the requirement can be achieved using:

• Flow
• Validation Rules
• Approval Processes
• Formula Fields
• Assignment Rules

If one of these tools can solve the problem efficiently, it is usually the preferred approach.

Keep One Trigger Per Object

Avoid creating multiple Apex Triggers on the same Salesforce object. When several triggers exist on a single object, the execution order becomes unpredictable, making debugging and maintenance much more difficult.

Instead, create a single trigger that delegates the business logic to one or more Trigger Handler classes.

This design keeps your code organized, reusable, modular, and easier to unit test.

Always Write Bulkified Code

Salesforce is designed to process records in bulk. A single transaction may contain one record, hundreds of records, or even thousands of records when executed through integrations, Data Loader, Batch Apex, or APIs.

Your Apex code should always work correctly regardless of how many records are processed in a single transaction.

To write efficient bulkified code:

• Query records once using collections.
• Process records using Lists, Sets, and Maps.
• Perform DML operations on collections instead of individual records.
• Handle multiple records in a single execution.

Design for Governor Limits

Every Apex transaction runs within Salesforce's Governor Limits, which protect the shared multitenant platform from excessive resource consumption.

Before writing Apex, always think about how efficiently your code uses platform resources.

Consider factors such as:

• Number of SOQL queries
• Number of DML operations
• CPU execution time
• Heap memory usage
• Callout limits

Efficient Apex minimizes resource usage, improves application performance, and prevents runtime exceptions caused by governor limit violations.

Follow Reusable Design Patterns

As Salesforce applications become larger and more complex, organizing Apex code properly becomes essential. Well-structured applications are easier to maintain, extend, debug, and test.

Instead of placing all business logic inside triggers or controllers, divide responsibilities into reusable layers.

Common design patterns include:

• Trigger Handler Pattern
• Service Layer
• Selector Classes
• Domain Layer
• Repository Pattern
• Enterprise Apex (fflib)