Defines the types of messages used in UML sequence diagrams. Each type determines the style and semantics of the message line.
Asynchronous - An asynchronous message, such as an event or signal that does not wait for a response.Create - A create message, used to indicate the instantiation of a new participant.Delete - A delete message, indicating the termination of a participant’s lifeline.Reply - A reply message, representing the return from a synchronous call.Self - A self-message, where the sender and receiver are the same participant.Synchronous - A synchronous message, typically a method call that waits for a response.