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how to delete all elements from hashmap in java?


HashMap

HashMap extends AbstractMap class and implements the Map interface. It contains the elements in key-value pair form. It not maintains any order for its elements. It not allowed duplicate key. A HashMap can have only one null key and multiple null values.

We can use clear() method to delete all elements from hashmap in java.

clear(): Removes all key-value pairs from this map.
Syntax: public void clear()

Example

package com.codesjava;
 
import java.util.HashMap;
 
public class Test {
	public static void main(String args[]){
		//Create HashMap object.
		HashMap<Integer, String> hashMap = new HashMap<Integer, String>();
 
		//Add objects to the HashSet.
		hashMap.put(4, "Roxy");
		hashMap.put(2, "Sunil");
		hashMap.put(5, "Sandy");
		hashMap.put(1, "Munish");
		hashMap.put(3, "Pardeep");
 
		//Print the HashMap object.
		System.out.println("HashMap elements:");
		System.out.println(hashMap);
 
		//Remove or delete all elements
		hashMap.clear();
		System.out.println("HashMap elements after clear operation:");
		System.out.println(hashMap);
	}
}

Output

HashMap elements:
{1=Munish, 2=Sunil, 3=Pardeep, 4=Roxy, 5=Sandy}
HashMap elements after clear operation:
{}
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