Fast UML is an open-source UML tool with a simple user interface pop-up free. Draw UML diagrams fast, export diagrams to png, jpg and clipboard.
It pretends to be the union between Violet and UMLet.
Dzine is a case tool for OOAD. Draw use case,interaction,class,deployment,ER Diagrams. Code generation in C++ and java and for SQL. Reverse engg design from code. Just put in your Java or C++ code and generate class diagrams.