TreeMap in Java

TreeMap in Java

A TreeMap contains values based on the key. It implements the NavigableMap interface and extends AbstractMap class.

Points to Remember

• It contains only unique elements.
• It cannot have null key but can have multiple null values.
• It is same as HashMap instead maintains ascending order.

import java.util.*;
class TreeMapDemo
{
public static void main(String args[])
{  
   
  TreeMap<Integer,String> tm=new TreeMap<Integer,String>();  
  tm.put(1,"Deo");  
  tm.put(2,"zen");  
  tm.put(3,"porter");  
  tm.put(4,"piter");  
  
 for(Map.Entry m:tm.entrySet())
 {  
   System.out.println(m.getKey()+" "+m.getValue());  
 }
 }  
}  

1,Deo
2,zen  
3,porter  
4, piter