Introduction

Scheduled Apex allows developers to schedule a class to run at specific intervals using CRON expressions or the Salesforce UI.

Key Features

• Automates recurring tasks.
• Flexible scheduling using CRON expressions.

Syntax for a Scheduled Apex Class

A class must implement the Schedulable interface.

global class ScheduledExample implements Schedulable {
    global void execute(SchedulableContext SC) {
        List<Account> accounts = [SELECT Id, Name FROM Account];
        for (Account acc : accounts) {
            acc.LastModifiedDate = System.now();
        }
        update accounts;
    }
}

Scheduling Through Salesforce UI

• Navigate to Setup > Apex Classes > Schedule Apex.
• Select the class and set the frequency, start date, and time.

Scheduling Using CRON Expression

String cronExp = '0 0 12 * * ?'; // Every day at 12 PM
System.schedule('Daily Account Update', cronExp, new ScheduledExample());

CRON Expression Format

Seconds Minutes Hours Day_of_month Month Day_of_week Optional_year

Example CRON expressions:

• 0 0 6 * * ? – Every day at 6 AM.
• 0 0 12 ? * MON-FRI – Every weekday at 12 PM.

Limitation for Asynchronous