The JPA diagram editor supports collections of embeddables and primitives.
To add an element-collection attribute of primitives, position the mouse cursor over the entity you want to manage and choose the Create Collection Attribute button. Each button has an informative tooltip that describes the relevant operation.
To add an element-collection attribute of embeddables, a collection of embeddable should be pinned to an entity or to another embeddable. In the Composition list of Palette, choose Embed Collection of Elements.
Click on the source entity or the embeddable of the Has-A relationship or press ESCAPE to cancel.
Click on the target embeddable of the Has-A relationship or press ESCAPE to cancel.
The Eclipse IDE creates and visualizes the Has-A relationship as well as the relevant embedded attribute in the entity, in which the embeddable is set.
The attribute will be mapped with @ElementCollection annotation.