XDoclet approach is used to store the UML in Java Doc with a specific tag @uml in following cases:
A XDoclet tag is composed of the following parts:
@namespace.tag-name attribute-name="attribute value"
Tags are grouped by namespaces, and have names that are unique within that namespace. Tags can have zero or more attributes, which are grouped in name="value" pairs. The namespace is a mechanism for making sure no name collision happens.
Tags exist at each Java elements such as package, class, method and field. As a general rule, if information can be determined by the name or type of a class, there will not be necessary to specify that information with a tag.
In eUML2 Modeler, UML artifacts use “ uml” as namespace.