问题
Given I have two Java classes Foo and Bar, and Bar has a getFoos() method that returns a List<Foo>.
In Java, all classes extend the parent class Object. List is an interface that extends the interface Collection, which in turn extends Iterable. All of these are provided by the Java core and do not require programming. However, they have methods that can be used or overridden. Interface hierarchy may be necessary to be known, for example a method that takes an Iterable<Foo> will accept a List<Foo>.
When drawing a class diagram from these in UML, how do I do with the well-known classes (Object) and interfaces (List, and its super interfaces Collection and Iterable)? Do I have to draw them into the diagram as well? Can I skip them completely? Is there a special symbol for these (a cloud would feel great to me)? What about not-that-common classes that should be qualified (i.e. if it would be an java.awt.List and not a java.util.List)?
回答1:
Your choice for how to deal with well-known classes will depend on how you plan on using your UML class diagram.
If the main purpose for creating a UML diagram is to communicate design details to a team, I would opt for not including well-know classes (not just from the JDK but also classes that are well-known in your context). The reason being that you want your message to be focused. Adding these well-known classes can quickly clutter your diagram while adding nothing to your message. For the same reason I typically exclude getters/setters and any information that is not essential to understanding the design. For classes that are not well-known I will include them because they communicate information that is not easily accessible to the team.
If your class diagram is going to be used in MDA, i.e. it will be used to generate a system implementation, then you have to include well-known classes.
回答2:
UML is not linked to any language, there is nothing in the norm about JDK classes.
A lot's of tools provide a profile with JDK classes already defined.
So you have to look in your tool if you get menu like "import profile" and look which profiles are available.
Two others solutions could be:
Define in your models the minimum set of JDK classes you need
Trying to write a java program to generate the XMI of JDK classes. Theoretically not so complicated, but the JDK includes JNI classes on which the introspection can not be used.
来源：https://stackoverflow.com/questions/47589182/how-to-go-with-well-known-classes-and-interfaces-in-an-uml-class-diagram