Appendix C. A History of UML

UML has not always been the de facto modeling language that it is today. In fact, not so long ago, everyone involved in complex system modeling was using a plethora of different modeling languagessome formal, some informaland each had its own associated development approach.

Nowhere was the problem more apparent than in software modeling. Object orientation had just become a fully recognized technique for developing software, and it did not take long for new modeling methods to start incorporating this revolutionary technique into their practices.

Unfortunately, even though object-oriented software modeling was seen as a good thing, the mess of different and conflicting approaches to modeling cancelled out a lot of the advantages that modeling promised. If you were designing using one modeling language and another member of your group was using another modeling language, the advantages of communicating designs to each other were completely lost. Software and system groups were forced to pick a modeling language, knowing that their choice was potentially a dangerous decision that could exclude other groups from easily joining the design effort.

This time of confusion and chaos in the software modeling world is now rather dramatically referred to as the "method wars." Three of the primary protagonists in these method wars were Grady Booch, Ivar Jacobson, and James Rumbaugh. Each of these innovators had their own software development methods and a modeling language with their own distinct notation. More importantly, they also headed up their own community of users that evangelized their approach to software modeling. It was these three approaches to software development and their associated languages and notation that were to form the basis of UML.