Difference between Sequence & Communication Diagram (UML)
What is the difference between sequence diagrams and communication (collaboration) diagrams in UML?
Answer
Quoting Wikipedia:
Communication diagrams show a lot of the same information as sequence diagrams, but because of how the information is presented, some of it is easier to find in one diagram than the other. Communication diagrams show which elements each one interacts with better, but sequence diagrams show the order in which the interactions take place more clearly.
In essence, collaboration diagram emphasizes on which objects interacts with each other while sequence diagrams put more emphasis on the actual order. But they are actually equivalent, in exception to a little more details visible in sequence diagrams, like when and by whom the object was created/destroyed.