Where is v visible?

Consider the following model

Where is v visible?
A . Only inside S
B . Only inside T
C . Only inside S and T
D . Inside the whole P

View Answer

Answer: C

Explanation:

In UML, visibility of an attribute is determined by the scope of the classifier it belongs to and its visibility markers. The attribute ‘v’ is marked with a ‘-‘ sign, indicating it is private. Being private, it would normally be visible only within the class it is defined in, which is ‘S’ in this case. However, since ‘T’ is a subclass of ‘S’ (as indicated by the generalization relationship, a line with a closed, unfilled arrowhead), it inherits the attribute ‘v’. Therefore, ‘v’ is visible in both ‘S’ and ‘T’.

Option A is incorrect because it does not consider inheritance. Option B is incorrect for the same reason. Option D is incorrect because a private attribute in a class is not visible to the entire package, only to the class itself and its subclasses.

The UML 2.5 specification states that a private member is only accessible within the namespace it is defined (section 7.5.3). Since ‘T’ is within the namespace of ‘S’ due to inheritance, ‘v’ is visible in both.