Java – Remove mapping from HashMap example

Example

In this example we are gonna see how to remove a specific mapping from HashMap using the key value of Key-value pair. We will be using the following method of HashMap class to perform this operation:

public Value remove(Object key): Removes the mapping for the specified key from this map if present and returns the Element value for that particular Key. More about remove method from Javadoc.

Complete Code:

import java.util.HashMap;

public class RemoveMappingExample {
 
 public static void main(String[] args) {
 
    // Creating a HashMap of int keys and String values
    HashMap<Integer, String> hashmap = new HashMap<Integer, String>();
 
    // Adding Key and Value pairs to HashMap
    hashmap.put(11,"Value1");
    hashmap.put(22,"Value2");
    hashmap.put(33,"Value3");
    hashmap.put(44,"Value4");
    hashmap.put(55,"Value5");
    hashmap.put(66,"Value6");
 
    // Displaying HashMap Elements
    System.out.println("HashMap Elements: " + hashmap);

    // Removing Key-Value pairs for key 33
    Object removedElement1 = hashmap.remove(33);
    System.out.println("Element removed is: " +removedElement1);
 
    // Removing Key-Value pairs for key 55
    Object removedElement2 = hashmap.remove(55);
    System.out.println("Element removed is: " +removedElement2);

    // Displaying HashMap Elements after remove
    System.out.println("After Remove:");
    System.out.println("--------------");
    System.out.println("HashMap Elements: " + hashmap);
 }
}

Output:

HashMap Elements: {33=Value3, 55=Value5, 66=Value6, 22=Value2, 11=Value1, 44=Value4}
Element removed is: Value3
Element removed is: Value5
After Remove:
--------------
HashMap Elements: {66=Value6, 22=Value2, 11=Value1, 44=Value4}