how to draw an interaction diagram

I have 开发者_如何学JAVA10 classes. I want to diagram out how they interact for my fellow developers. What diagram type is the best for this?

IE class 1 requests data object a from class 2 etc

A final answer does not seem to be possible. I recommend to create one (or more) sequence diagram(s) depending on the complexity of your use cases. A nice tutorial is available here (just googled for 'uml sequence diagram').

Edit: Just a reminder. UML can become very complex, so you may not want to document all interactions in detail. Describe the high-level concepts and keep THIS in mind.