Question

The UML is a large and complex modeling language. How can an IT professional tell when a UML diagram is correct and not just visually pleasing?

Answer 1

1)

Every module or class should have responsibility over a single part of the functionality provided by the software, and that responsibility should be entirely encapsulated by the class. All its services should be narrowly aligned with that responsibility.

2)

The Open-Closed Principle Software entities (classes, modules, functions, etc.) should be open for extension, but closed for modification; that is, such an entity can allow its behavior to be extended without modifying its source code.

3)

Liskov Substitution Principle -> Subtypes must be able to replace their parent types.