In this, the final part of our series of experts from Use Case Driven Object Modeling with UML: Theory and Practice Matt Stephens and Doug Rosenberg show you how to draw lean, purposeful sequence diagrams that are driven from the use cases and preliminary design. As before, this chapter opens with the following "you are here" …
Are they fit for any purpose?
A sequence diagram usually only represents one path, out of many, through a use case. They don't handle exceptions very well and they don't handle message content particularly well.
All of this is evident in the examples given.
Why not use BPMN - Activity diagrams ++ - instead?
Do DB operations always succeed?
I think not. The diagram needs another alternate course for the save operation failing.
Add a semi colon & compile
There is no point to diagramming something when all you need to do is add semi colons to the text in the diagram and compile.
But this may be an artefact of the fact that only simple examples are used in texts as I can see the utility of these diagrams when there is complicated set of steps at a higher level than a single class or that involves interaction with numerous classes
I have small problem with this.
When you see words like JDBC, DAO, etc in diagram instead of just data base access? Aren't the use ( UML, whatever.. ) diagrams supposed to show use cases, what, etc instead of one of hundreds (thousands?) of possibles ways to implement a solution? It says Spring/JSP project but what if things change next week? How valid it is then? Not to blame the book but solutions should work not matter what the supporting architecture is.