Unified Modeling Language (UML)

To develop a complex software system, it can be helpful to develop a model of that system
One can experiment with the model to determine whether it exhibits the desired system behavior
Once the model is satisfactory, the software can be developed to match the model
UML is a large, complex language for describing models of many different types
Software tool support is extremely valuable when using UML
Thirteen types of diagrams in three categories:
- Structure diagrams show the architecture of the system
  - An example of these is the diagrams that BlueJ uses for your classes
- Behavior diagrams show what components should do
  - State machines
  - User interactions
- Interaction diagrams show how components communicate