Collections Mappings:
If an entity or class has collection of values for a particular variable, then we can map those values using any one of the collection interfaces available in java. Hibernate can persist instances of java.util.Map, java.util.Set, java.util.SortedMap, java.util.SortedSet, java.util.List, and any array of persistent entities or values.

Collection type Mapping and Description
java.util.Set This is mapped with a element and initialized with java.util.HashSet
java.util.SortedSet This is mapped with a element and initialized with java.util.TreeSet. The sort attribute can be set to either a comparator or natural ordering.
java.util.List This is mapped with a element and initialized with java.util.ArrayList
java.util.Collection This is mapped with a or element and initialized with java.util.ArrayList
java.util.Map This is mapped with a element and initialized with java.util.HashMap
java.util.SortedMap This is mapped with a element and initialized with java.util.TreeMap. The sort attribute can be set to either a comparator or natural ordering.

Set Mapping