Remove mapping from HashMap example

This is an example of how to remove mapping from a HashMap, that is removing a key value pair from a HashMap. Removing mapping from a HashMap implies that you should:

• Create a new HashMap.
• Populate the hashMap with elements, with the put(K key, V value) API method of HashMap.
• Invoke the remove(Object key) API method of HashMap, to remove a key value pair from the hashMap. It returns either the value mapped with the key previously or null if no value was mapped.

Let’s take a look at the code snippet that follows:

package com.javacodegeeks.snippets.core;

import java.util.HashMap;
 
public class RemoveMappingHashMap {
 
  public static void main(String[] args) {
 
    // Create a HashMap and populate it with elements
    HashMap hashMap = new HashMap();
    hashMap.put("key_1","value_1");
    hashMap.put("key_2","value_2");
    hashMap.put("key_3","value_3");
 
    System.out.println("HashMap contains : " + hashMap);

    /*

Object remove(Object key) operantion removes a key value pair from HashMap. 

It returns either the value mapped with the key previously or null if no value was mapped.     
    */
    Object value = hashMap.remove("key_2");

    System.out.println("After removing value : " + value + " HashMap contains : " + hashMap);
  }
}

Output:

HashMap contains : {key_3=value_3, key_2=value_2, key_1=value_1}
After removing value : value_2 HashMap contains : {key_3=value_3, key_1=value_1}

 
This was an example of how to remove mapping from a HashMap in Java.