The properties you create are not actually turned into instance variables. They are put into a Map keyed on the property name. For example, the DynaActionform does not have a getFirstName() or a setFirstName() method. It has a get(
String) method and a set(String, String) method. If you want to set the value of the first name field, you do it like this:
dynaForm.set("firstName", "John");
To get the value, you do it like this:
String firstName = (String)dynaform.get("firstname");
Because of this awkwarness in using the getter and setter, I really don't like DynaActionForms, and much prefer writing my own subclasses of ActionForm.