Any UML guru's around here?

[Jumpem]

I have class diagrams with several different classes in them. How do I know when to use a solid arrow to connect hem, and when to use a dotted arrow?

 

[Descartes]

The dotted line indicates a dependency, and the solid a generalization. The latter should be pretty obvious, but the former usually represents any interaction of one entity from another; for example, one class instantiating another. I'd Google around for more description if you wish to know its significance in OOAD.