Solution: The {abstract} syntax is an example of a constraint. There is no special structure for the text between the braces; it should simply provide a short clarification of any conditions that may apply to the element.

Solution: Attributes describe a class’s properties. Attributes are listed in the section directly beneath the class name.

Solution: The visibility symbol is followed by the name of the attribute.

Solution: In the case of aggregation, the contained objects are a core part of the container, but they can also be contained by other objects at the same time.

Solution: In composition, the contained object can be referenced by its container only. It should be deleted when the container is deleted.

Solution: A sequence diagram is object based rather than class based. It is used to model a process in a system step by step.

Solution: A unidirectional association has single-headed arrow.

Solution: Available to the current class and its subclasses only.

Solution: Operations describe methods, or more properly, they describe the calls that can be made on an instance of a class.

Solution: The UML describes the inheritance relationship as a generalization. This relationship is signified by a line leading from the subclass to its parent. The line is tipped with an empty closed arrow.