This is an example of how to remove all mappings from a HashMap, that means removing all key value pairs in a HashMap. Removing all key value pairs 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
clear()API method of HashMap, to remove all mappings of the hashMap. The map will be empty after this call returns.
Let’s take a look at the code snippet that follows:
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 | package com.javacodegeeks.snippets.core;import java.util.HashMap; public class ClearHashMap { 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); // void clear method() removes all mappings of HashMap class hashMap.clear(); System.out.println("HashMap contains : " + hashMap); }} |
Output:
HashMap contains : {key_3=value_3, key_2=value_2, key_1=value_1}
HashMap contains : {}
This was an example of how to remove all mappings from a HashMap in Java.
