You can use Force.com code to add business logic to applications, write database triggers, and program controllers in the user interface. Force.com code has tight integration with the database, query language, and Web services.
Force.com includes an Eclipse-based IDE for creating, modifying, testing, and deploying Force.com applications.
Force.com code has a syntax that will be familiar to Java and C# programmers. It includes classes, interfaces, constants, class variables, and annotations.
Force.com code has strong ties with the Force.com database. You can use it to create, persist, and update database objects. You can also query the database, iterate over results, and provide database triggers.
Force.com code makes it easy to call external Web services and to expose methods as Web service endpoints.
You can annotate Force.com code to execute asynchronously. This setup gives you more flexibility when developing custom business logic and helps improve response times.