What are the Limitations of Apex?

Apex radically changes the way that developers create on-demand business applications, but it is not currently meant to be a general purpose programming language. As of this release, Apex cannot be used to:

Render elements in the user interface other than error messages
Change standard functionality—Apex can only prevent the functionality from happening, or add additional functionality
Create temporary files
Spawn threads

Tip

All Apex runs on the Force.com platform, which is a shared resource used by all other organizations. To guarantee consistent performance and scalability, the execution of Apex is bound by governor limits that ensure no single Apex execution impacts the overall service of Salesforce. This means all Apex code is limited by the number of operations (such as DML or SOQL) that it can perform within one process.

All Apex requests return a collection that contains from 1 to 50,000 records. You cannot assume that your code only works on a single record at a time. Therefore, you must implement programming patterns that take bulk processing into account. If you do not, you may run into the governor limits.