UML Papyrus association notation

Question

I am creating an UML class diagram on Papyrus but I can't understand the notation used for associations. When an association is set to be navigable, the tool adds a black dot on the tip of the arrow as default notation. I was able to remove the dot by changing the member end owner from classifier to association. What is the conceptual difference between the two? I can't find any discussion on the concept of classifier in my UML book...

Thank you!!

PS: I'm using papyrus 4 on Eclipse Juno

Answer 1

If you know that the class A has some way of referencing B, by some function or attribute reference, for example, you make arrow from A to B. The instance of B is NAVIGABLE from A, but probably is not an attribute of A.

If you know that an of attribute A is one or more references to B instance, you can draw not only arrow, but also the "dot" at its end.

Very often people simply use arrow in both cases. But strict use of the dot can provide additional information.

Answer 2

As described in this UML Association Reference, the black dot's semantic is :

It could be interpreted as showing that the model includes a property of the type represented by the classifier touched by the dot

(See the link for more information)