User classes are functionally equivalent to system classes, that is, any operation you can perform with a system class in the 4GL code of an executable component can be done with a user class. However, although the 4GL syntax for invoking a method on a user class object is identical to that of a system class, you often handle user classes differently from system classes.

For example, the following code invokes the Hire method on a temporary employee:

In all likelihood, however, most values for the Hire method are input at runtime by the user typing into form fields. The form fields are children of a composite field that is mapped to the TempEmployee user class. Because these values are automatically available to any method invoked on that composite field, you may not need to pass method parameters programmatically as shown in the code example.