Remove all values from TreeMap in Java

Use the clear() method to remove all values from TreeMap.

Let us first create a TreeMap −

TreeMap<Integer,String> m = new TreeMap<Integer,String>();

Add some elements to the TreeMap −

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");

Let us now remove all the values −

m.clear();

The following is an example to remove all values 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()); m.clear(); System.out.println("\nTreeMap after removing all elements = "+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 all elements = {} Size of TreeMap now = 0