UML default visibility

Question

is there a default visibility in UML2 if I don't (want to) add one of the four reserved visibilities? As I know there is + for public, - for private, # for protected and ~ for package.

Or is the default depend on the implementation language that should be used, e.g. package for Java or private for C++?

Thanks so far.

Answer 1

If you don't add it then it's a don't care. Languages itself have their own rules and UML does not know how a language will treat it. The same goes for tools. They place one of the symbols (either public or private) as default and you eventually can change a default to something else. But again UML does not care.

Depending on how you use it you can tell the reader that a missing symbol will mean this or that.

Edit 1: Thanks to @xmojmr digging into the UML spec and the great critic uml-diagrams.org here are two statements. OMG first (SS2.4.1):

7.3.38 Package (from Kernel)...The query makesVisible() defines whether a Package makes an element visible outside itself. Elements with no visibility and elements with public visibility are made visible" and "7.3.39 PackageableElement (from Kernel)... visibility...Default value is public

and from http://www.uml-diagrams.org/property.html

Note, that there is no default visibility. Also, visibility may be suppressed from being displayed on a diagram, even if it has some value in the model (e.g. stored by UML tool). So, if visibility is not shown on a diagram, it was either not specified or suppressed

Please also note that my original statement was just an expression of my experience from using UML in the real world. Feels good to see that my experience seems to be in synch with the theories ;-)

Edit 2: Looking into the 2.5 specs I found this in chap. 7.8 Classifier Descriptions on p. 48:

Attributes

- visibility : VisibilityKind [0..1] = public

A PackageableElement must have a visibility specified if it is owned by a Namespace. The default visibility is public.

Constraints

- namespace_needs_visibility

A PackageableElement owned by a Namespace must have a visibility.

inv: visibility = null implies namespace = null

So it says the default is public. But the constraint says it must have a visibility. Which to me means that you need to specify it?

If you don't understand definition, read the definition for definition :-/