Introduction
The Unified Modeling Language(UML) is an object-oriented analysis and design that evolved as a result of the combined work of James Rumbaugh, Grady Booch, and Ivar Jacobson. In 1997, a UML consortium(which include Microsoft, Hewlett-Packard, Oracle, MCI Systemhouse, IBM, IntelliCorp and more) submitted the 1.1 version of the UML to the Object Management Group(OMG). Since then, UML has become a de facto standard in the software industry, and it continues to evolve.

UML
- consists of a number of graphical elements that combine to form diagrams
- describes what the system is supposed to do, doesn't tell how to implement the system