Asynchronous Apex

💬 In plain words: The @future annotation is the original "fire-and-forget" asynchronous tool in Salesforce. You tag a static method, and the platform runs it later. However, its strict limitations—only accepting primitive data types, no ability to chain jobs, and no traceable Job ID—are the exact reasons Queueable Apex was created to replace it. Today, @future is mainly used as a quick escape hatch for Mixed-DML errors. 📌 The Problem: In legacy code, a trigger might call @future(callout=true) to push data to an external ERP. It works fine until a developer tries to trigger that same logic from a Batch Apex job, resulting in the dreaded error: "future method cannot be called from a future or batch method." The Fix: The modern solution is to rewrite that logic as a Queueable class, leaving @future purely for resolving quick Setup vs. Non-Setup object conflicts (Mixed-DML). 🎬 Real-Life Example: The Stale Snaps...

💬 In plain words: Synchronous (Sync) means the user waits for the process to finish, and you are constrained by tight platform limits. Asynchronous (Async) means the work happens later in the background, giving you much higher limits. Move work to async when it is slow (like API callouts or heavy calculations) or involves massive amounts of data. However, remember that async means "eventually." Do not use it if the user needs to see the result immediately on their screen. 📌 Real-Life Example: A user clicks "Save" on an order. You need to update the Salesforce record NOW (sync). But do you also need to notify your SAP system and recalculate the customer's yearly totals instantly? No. The user shouldn't have to stare at a loading spinner waiting for SAP to respond. Publish an event and queue the recalculation in the background. Think of sync as the fast lane for the user, and async as the freight lane for the heavy lifting. ...

💬 In plain words: The error System.CalloutException: You have uncommitted work pending. Please commit or rollback before calling out occurs when your code changes the database (like using an insert or update statement) and then tries to send an HTTP callout to an external server in the exact same synchronous process. Salesforce actively blocks this to prevent database locks from hanging open while waiting for external servers to reply. When developing custom backend integrations in Salesforce, encountering the "uncommitted work pending" error is almost a rite of passage. Understanding why this strict transaction limit exists—and how to architect your Apex to respect it—is the key to building resilient, enterprise-grade system integrations. 📌 Key Points The Root Cause: Mixing Data Manipulation Language (DML) and HTTP Callouts in the wrong order. The Golden Rule: You can perform a Callout before DML, but you can never perform DML befo...

In plain words: Think of the Apex Flex Queue as a digital waiting room for your batch jobs. Salesforce can run up to 5 batch jobs at the same time. The Flex Queue holds up to 100 additional batch jobs in a Holding status, automatically feeding them into execution as processing slots open up. Managing large-scale data processing in Salesforce requires balancing high data volumes with strict multi-tenant governor limits. While synchronous transactions must complete within milliseconds, Batch Apex handles millions of records asynchronously. The Apex Flex Queue is the core platform infrastructure that governs how these batch jobs are queued, prioritized, and executed without failing due to concurrency constraints. 1. How the Apex Flex Queue Operates Prior to the Flex Queue, submitting a batch job when all processing threads were full resulted in immediate job rejection. The Flex Queue eliminates this limitation by introducing the Holding status: Holdi...

Technical interviews for Salesforce developers evaluate not just your syntax knowledge, but how well you understand governor limits, asynchronous design patterns, and modern UI architectures. Here is a curated guide to 15 essential Salesforce interview questions with clear explanations and best-practice examples. In plain words: Salesforce technical interviews test your real-world problem solving: how you process high-volume data within execution limits, decouple integrations, and coordinate communication across UI components. 1. Asynchronous Apex & Batch Processing Q1: What are the batch size boundaries in Batch Apex? When invoking Database.executeBatch(instance, scopeSize) , the batch execution boundaries are: Default Batch Size: 200 records. Minimum Batch Size: 1 record. Maximum Batch Size: 2,000 records. Real-Life Scenario: If your batch's execute() method makes external callouts or executes heavy transactional...