Do you know collection classes in Java?
By:smashplus
Do you know collection classes in Java?
Quick Answer:
Collection is the way to store multiple items in a single unit.
The Collection is the base interface.
- java.util.Collection is the root interface. -->Contains methods size(), iterator(), add() etc.
- java.util.List,
- Can contain duplicate elements
- java.util.Set
- Cannot contain duplicate elements, Cannot do random access.
- java.util.Queue
- java.util.Map doesn't inherit from the Collection interface
Implementation classes:
- ArrayList
- LinkedList
- HashMap, TreeMap
- HashSet, TreeSet
| HashSet | TreeSet |
| Implementation of the set interface backed by a Hashmap | |
| no guarantee for iteration order of the set and permits the Null element | |