Everybody has its own opinion about the Unified Modeling Language but I think it’s interesting to collect some UML opinions expressed by the people that created the language in the first place some twenty years ago.
Grady Booch’s views on UML
The UML should be used to reason about alternatives. Put up some diagrams. Throw some use cases against it. Throw away those diagrams then write some code against you best decision. Repeat
When we began with the UML, we never intended it to become a programming language
We never got the notation for collaborations right. Component and deployment diagrams needed more maturing.The UML metamodel became grossly bloated, because of the drive to model driven development. I think that complexity was an unnecessary mistake.
I rather still like the UML 🙂 Seriously, you need about 20% of the UML to do 80% of the kind of design you might want to do in a project – agile or not – but use the UML with a very light touch: use the notation to reason about a system, to communicate your intent to others…and then throw away most of your diagrams.
one should only use a graphical notation for those things that cannot easily be reasoned about in code
and a few recent tweets as well
IMHO the UML standard went off the rails when it was made overly complex to support MDD…the UML is not a prog lang https://t.co/aFabrgpAug
— Grady Booch (@Grady_Booch) August 2, 2016
The UML is not a dessert topping and a floor wax. https://t.co/GWCXKbqqDk
— Grady Booch (@Grady_Booch) August 4, 2016
ending up in a slightly positive note
I never left 🙂 (I still use it in my work) https://t.co/8x4SDiL6DF
— Grady Booch (@Grady_Booch) August 2, 2016
And one surprising fact that you maybe didn’t know. Grady Booch confessing how UML saved his life!
When I was diagnosed with an aneurysm of the ascending aorta, I remember laying in a CT machine, then I remembered I knew the team who wrote its software…and they used the UML.
So yes: that which Jim, Ivar, and I conceived then tens of thousands nurtured saved my life. https://t.co/zCMpZd3HwU
— Grady Booch (@Grady_Booch) March 14, 2019
Ivar Jacobson’s opinion on UML
He starts by stating loud and clear that rumors of the death of UML are all false. Other highlights:
UML is not the silver bullet it was sold as ten years ago. Nor it is as bad as academicians, agilistas and competitors claimed five years ago
There are two major challenges to be addressed: complexity of the UML specification itself, and the need to describe UML in coherent subsets that address the actual needs of users in particular domains
UML has become complex and clumsy. For 80% of all software only 20% of UML is needed.
If UML is used in a smart way, it is very practical and results in products with higher value. UML is a great language to create architectures. It works very well for agile teams.
Bran Selic on UML’s complexity
Bran defends that in fact UML is not as complex as you may think: “The complexity of UML is often cited as one of its primary drawbacks. In arguing this, many people will point to the apparent simplicity of programming languages such as Java. However, while Java is relatively simple on its own, you have to consider how much of the necessary complexity has been swept under the rug of class libraries? As far as I can tell, you cannot write anything remotely useful in Java unless you are also proficient with at least some of the core Java libraries. In environments such as J2EE or Eclipse, the minimum level of proficiency goes up even further — exceeding in complexity anything that UML requires.
Consequently, although I do think that UML is bloated needlessly, I think it is mere pittance compared to what you find in the so-called “mainstream” languages used for most applications development.
The problem is that we are trying to solve complex problems. As any carpenter can tell you, complex problems require complex tools. ”
Or as he puts it:
I can give you 1000 examples of UML being bad but “uml is big” is not one of them. Too big for what?
Other insightful quotes:
UML is the worst modeling language except for all the others
The worst UML book you can buy is “UML Distilled” (the criticism refers to the fact that the book only covers the syntax of UML)
Do you have other quotes you would like to share? Please add a comment!
ICREA Research Professor at Internet Interdisciplinary Institute (UOC). Leader of the SOM Research Lab focusing on the broad area of systems and software engineering