In a sequence diagram, you can drag and drop a class or an interface
from
the Package Explorer to the Sequence Diagram Editor and get a new
instance.
You need first to create the
classifier in the model if it doesn't already exist by a drag and drop from the Package Explorer
to the Sequence Diagram
Click on the Add new property icon and Select the
Select Existing Element menu
Select the newly created class in the
model explorer and click on the Ok button
The Java Class will be added to the
sequence diagram
