In the Project Explorer, select the project that you are using or want to use for your entities.
In the context menu, choose JPA Tools -&grt; Open Diagram .
In the Entities list of the Palette, choose (Entity), then click the diagram area.
The Eclipse IDE creates the new entity with a predefined name and a primary key.
To display a single entity, copy the entity using drag and drop from the Project Explorer to the JPA diagram.
To display all entities, click the JPA diagram with the secondary mouse button and choose Show All Entities, or copy the JPA Content node from the project in the Project Explorer to the JPA diagram, using drag and drop.