Remove all mappings from TreeMap example – Java

This is how to remove all the key-value mappings from TreeMap and make it empty. We are using clear() method of TreeMap class to perform this update.

import java.util.TreeMap;
 
public class RemoveAllExample {
 
  public static void main(String[] args) {
 
    // Create a TreeMap
    TreeMap<String, String> treemap = new TreeMap<String, String>();
 
    // Add key-value pairs to the TreeMap
    treemap.put("Key1","Item1");
    treemap.put("Key2","Item2");
    treemap.put("Key3","Item3");
    treemap.put("Key4","Item4");
    treemap.put("Key5","Item5");
 
    // TreeMap elements before calling clear()
    System.out.println("Before: TreeMap contains: "+treemap);
 
    // Make TreeMap empty
    /* public void clear(): It removes all of the mappings from 
     * this map. The map will be empty after this call returns.
     */
    treemap.clear();
 
    //TreeMap elements after calling clear()
    System.out.println("After: TreeMap contains: "+treemap);
  }
}

Output:

Before: TreeMap contains: {Key1=Item1, Key2=Item2, Key3=Item3, Key4=Item4, Key5=Item5}
After: TreeMap contains: {}

Reference:
TreeMap – clear() method