Time complexity to SEARCH and insert
| O(1)
| O(log n)
| O(1)
|
Iteration Order
| Random
| Sorted order according to the natural ordering
| Sorted order according to the insertion order
|
Is Null key support
| Allowed
| Not allowed
| Allowed
|
Is thread safe
| No, we need to collections utility to make thread safe
| No, we need to collections utility to make thread safe
| No, we need to collections utility to make thread safe
|
Interface
| Map
| Map, SortedMap, NavigableMap
| Map
|
Data structure support
| LinkedList
|
| DoublyLinkedList
|
Application
| Normal processing, faster retrieval ConcurrentHashMap we can USE as per the need
| Required when we do the sorting and navigable features need as per the use case.
| Required when we need to maintain the insertion order and when we need to implement the LRU cache.
|
Key requirement
| equals() and HASHCODE() method need to overwritten
| Along with equals() and hashcode(), the comparator to implement.
| equals() and hashcode() method need to overwritten
|
Syntax
| public class HashMap extends AbstractMap
implements Map, Cloneable, Serializable
| public class TreeMap extends AbstractMap implements
NavigableMap, Cloneable, Serializable
| public class LinkedHashMap extends HashMap
implements Map
|
