Elements of a timing diagram include:
Role
object
lifeline
message (arrow)
Question: On the arrow, there will be a function method. Does this method belong to the object pointed to by the arrow, or the source object of the arrow, which was always confusing before ?
Answer: This method belongs to the object pointed to by the arrow, not the source object of the arrow, make no mistake
This can be seen at the following URL:
http://www.uml.org.cn/oobject/201009081.asp
This is reflected in the sequence diagram of "Spring Technology Insider 2nd Edition"