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.
