An Activity diagram is a visual representation of any system's activities and flows of data or decisions between activities. When you click the Diagram editor tab for an Activity diagram, the IDE displays a specific selection of icons in the IDE Modeling Palette. Activity diagrams provide a very broad view of a business process.
The diagram may be used to:
• Describe activities and flows of data or decisions between activities
• Provide a broad view of business processes
• Describe the activities that occur within a use case
• Show many different activities using different discrete symbols
• Show parallel threads