{"id":20233,"date":"2026-08-19T09:15:47","date_gmt":"2026-08-19T09:15:47","guid":{"rendered":"https:\/\/dianapps.com\/blog\/?p=20233"},"modified":"2026-08-19T11:03:02","modified_gmt":"2026-08-19T11:03:02","slug":"apex-programming-guide","status":"publish","type":"post","link":"https:\/\/dianapps.com\/blog\/apex-programming-guide\/","title":{"rendered":"Apex Programming Guide: Triggers, Testing and Best Practices"},"content":{"rendered":"

Apex is easy to learn and hard to write well, as the syntax takes about a week while the constraints take a quarter.<\/span><\/p>\n

Most Apex problems in production aren\u2019t syntax errors; they\u2019re code that worked perfectly against ten records and collapsed against fifty thousand, or a trigger that fires twice because nobody added a recursion guard, or a class that passes 78% coverage while asserting nothing at all.<\/span><\/p>\n

This guide covers the language and then the parts that actually break.<\/span><\/p>\n

Quick Answer:<\/b> Apex is Salesforce\u2019s server-side language: Java-like syntax running inside hard per-transaction limits. Bulkify everything and assume 200 records. One trigger per object, delegating to a handler. Use Queueable as your default async option. Enforce security with <\/span>WITH USER_MODE<\/b> rather than manual FLS checks. And treat 75% coverage as a deployment gate not a quality target.<\/span><\/p><\/blockquote>\n

What Is Apex?<\/b><\/h2>\n

Apex is Salesforce\u2019s proprietary, strongly typed, object-oriented programming language. It runs on Salesforce servers, executes in the context of a database transaction, and has SOQL and DML built directly into the syntax rather than bolted on through a driver.<\/span><\/p>\n

You reach for it when the declarative tools can\u2019t express what you need – complex bulk processing, callouts with retry logic, recursion control, transactional rollback, or logic that has to be unit-tested to a standard Flow can\u2019t reach. See <\/span>Flow vs Apex<\/span> for where that line sits.<\/span><\/p>\n

Apex Looks Like Java. It Doesn\u2019t Behave Like Java.<\/b><\/h2>\n

\"Comparison<\/p>\n

Comparison of Java and Apex across resource limits, threading, static state, data access, security, testing, and deployment<\/span><\/i><\/p>\n

The three that catch experienced developers hardest:<\/b><\/p>\n