Use Case Diagrams
Use case diagrams model the functionality of system using actors and use cases.

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Class Diagrams
Class diagrams are the backbone of almost every object oriented method, including UML. They describe the static structure of a system.

Object Diagrams
Object diagrams describe the static structure of a system at a particular time. They can be used to test class diagrams for accuracy.

Package Diagrams
Package diagrams are a subset of class diagrams, but developers sometimes treat them as a separate technique. Package diagrams organize elements of a system into related groups to minimize dependencies between packages.

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Activity Diagrams
Activity diagrams illustrate the dynamic nature of a system by modeling the flow of control from activity to activity. An activity represents an operation on some class in the system that results in a change in the state of the system. Typically, activity diagrams are used to model workflow or business processes and internal operation.

Statechart Diagrams
Statechart diagrams describe the dynamic behavior of a system in response to external stimuli. Statechart diagrams are especially useful in modeling reactive objects whose states are triggered by specific events.

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Sequence Diagrams
Sequence diagrams describe interactions among classes in terms of an exchange of messages over time.

Collaboration Diagrams
Collaboration diagrams represent interactions between objects as a series of sequenced messages. Collaboration diagrams describe both the static structure and the dynamic behavior of a system.

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Component Diagrams
Component diagrams describe the organization of physical software components, including source code, run-time (binary) code, and executables.

Deployment Diagrams
Deployment diagrams depict the physical resources in a system, including nodes, components, and connections.

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The Stucture of UML just as figure below: