Spring offers the following types of collection configuration elements:
The <list> type is used for injecting a list of values, in the case that duplicates are allowed.
The <set> type is used for wiring a set of values but without any duplicates.
The <map> type is used to inject a collection of name-value pairs where name and value can be of any type.
The <props> type can be used to inject a collection of name-value pairs where the name and value are both Strings.