UMLet 12.0 (beta)
Free UML Tool for Fast UML Diagrams
UMLet is a free, open-source UML tool with a simple user interface:
draw UML diagrams fast,
produce sequence and activity diagrams from plain text,
export diagrams to eps, pdf, jpg, svg, and clipboard,
share diagrams using Eclipse, and
create new, custom UML elements.
UMLet runs stand-alone or as Eclipse plug-in on Windows, OS X and Linux.
(Also, check out its sister tool PLOTlet to create chart grids and our other tools.)
New in version 12.0beta: Automatically create UML diagrams from Java source code or class files; new graphical element types (beta), with syntax completion
New in version 11.5: Improved handling of special characters; config file writes to home dir; new: open multiple diagrams
If you like UMLet, please vote for us at EclipsePluginCentral!
Custom Elements Tutorial
Sample UMLet diagrams