Java LinkedHashMap class

• A LinkedHashMap contains values based on the key. It implements the Map interface and extends HashMap class.
• It contains only unique elements.
• It may have one null key and multiple null values.
• It is same as HashMap instead maintains insertion order.

Hierarchy of LinkedHashMap class:

Example of LinkedHashMap class:

1. import java.util.*;  
2. class TestCollection14{  
3.  public static void main(String args[]){  
4.    
5.   LinkedHashMap<Integer,String> hm=new LinkedHashMap<Integer,String>();  
6.   
7.   hm.put(100,"Amit");  
8.   hm.put(101,"Vijay");  
9.   hm.put(102,"Rahul");  
10.   
11. for(Map.Entry m:hm.entrySet()){  
12.    System.out.println(m.getKey()+" "+m.getValue());  
13.   }  
14.  }  
15. }  

Output:100 Amit
       101 Vijay
       103 Rahul