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Know about APEX

Apex is a proprietary language  that sits within Force.com platform and it can only be invoked within triggers and classes(write triggers and classes).(Which means its not a general purpose language which can be used out side Force.com)

Apex is complied and executed in cloud so does not need any dedicated Hardware or Software and it runs on Salesforce.com Servers.

Apex is not technically auto-upgraded with each new application release because it is saved with a specific version of the API. However, like other Force.com features, Apex automatically works with the new version of Salesforce application.

With Apex, we can only create specific functionalities such as triggers on objects and new Salesforce Web Services. We CANNOT create entirely new application written only in Apex out of Force.com.
This is the one of the difference between Tradition code and Apex code.
Traditional code allows users to create all type of applications like small, stand alone to complex and web based application.

Apex  is object oriented programming language that supports inheritance and polymorphism and runs in a multitenant environment and is Case - INSENSITIVE.

Apex has 2 main components:- Classes & Triggers.
i)Trigger is a Apex method/procedure which will be automatically executed during a DML operations like -Insert/Update/Delete operations of a particular object.
ii)Class is a library of attributes and methods.very much similar to Java or C# classes.

Apex is also used to write Visualforce controllers(similar to Classes). which provide data and actions to Visualforce pages when the pages controlled by this data and action are rendered.

Apex is also used to write Web Services using Web Services API and key word [webservices].This means that Apex is also available via AJAX toolkit

Code Compilation
In the Force.com environment, when a user saves Apex code its sent to Apex Server. at Apex server the code is complied and checked for syntax errors. Only when no errors are found the code is saved to the Force.com DataBase. else an errors are thrown back to user and code will not be saved.
But users use Force.com IDE(Intergrated Development Environment)  - Ecplise. The code gets save to local hard drive(Local system) irrespective of any errors.



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