Remove a value from TreeMap in Java

Use the remove() method to remove a value from TreeMap.

Create a TreeMap first and add some elements −

TreeMap<Integer,String> m = new TreeMap<Integer,String>();
m.put(1,"PHP");
m.put(2,"jQuery");
m.put(3,"JavaScript");
m.put(4,"Ruby");
m.put(5,"Java");
m.put(6,"AngularJS");
m.put(7,"ExpressJS");

Now, let’s say you need to remove a value with key 5. For that, use the remove() method −

Object ob = m.remove(5);

The following is an example to remove a value from TreeMap −

Example

 Live Demo

import java.util.*;
public class Demo {
   public static void main(String args[]) {
      TreeMap<Integer,String> m = new TreeMap<Integer,String>();
      m.put(1,"PHP");
      m.put(2,"jQuery");
      m.put(3,"JavaScript");
      m.put(4,"Ruby");
      m.put(5,"Java");
      m.put(6,"AngularJS");
      m.put(7,"ExpressJS");
      System.out.println("TreeMap Elements...");
      Collection res = m.values();
      Iterator i = res.iterator();
      while (i.hasNext()) {
         System.out.println(i.next());
      }
      System.out.println("TreeMap size = "+m.size());
      // Remove an element
      Object ob = m.remove(5);
      System.out.println("\nTreeMap after removing a single element...\n "+m);
      System.out.println("Size of TreeMap now = "+m.size());
   }
}

Output

TreeMap Elements...
PHP
jQuery
JavaScript
Ruby
Java
AngularJS
ExpressJS
TreeMap size = 7
TreeMap after removing a single element...
{1=PHP, 2=jQuery, 3=JavaScript, 4=Ruby, 6=AngularJS, 7=ExpressJS}
Size of TreeMap now = 6