If you’re interested in setting properties per entity object definition per user, the easiest way is probably to store them, with a key that indicates both the definition and the property (e.g., the string “mypackage.MyEntityDefName_MyProperty”) on the Hashtable returned by ApplicationModuleImpl.getSession().getUserData() for your application module. Then, create a method on your EntityObjectImpl custom framework subclass (assuming you need to use this property within particular EO instances, even though you want to store it once) like so:

public (or protected) Object getCustomProperty(String propName) {
Hashtable properties = getDBTransaction().getSession().getUserData();
String propKey = getEntityDef().getFullName() + ‘_’ + propName;
return properties.get(propKey);
}