JSF is a Model/View/Controller (MVC) framework where you write the View templates (xhtml) and the Models (backing beans) and the Controllers are supplied by JSF itself.
If you submit a form with valid data in it, JSF will automatically invoke the appropriate "set" methods for the properties you referenced in the backing bean. You don't have to write any Java code.
Conversely, whatever value you set in a backing bean will be reflected in the View (web page) the next time the View is (re)displayed. Again, done automatically, as JSF's Controllers invoke the propery "get" methods.
Within the action method (actions are not part of MVC, they're the business interface to the Model) the action code can likewise obtain the value posted to the backing bean from the form by invoking the property "get" method. Or by direct field access, if you prefer, but I like to use the get/set methods, since they're easier to trace and the compiler optimizes them anyway.
An IDE is no substitute for an Intelligent Developer.