We can use keySet() method to get list of keys from hashmap java.
keySet(): Returns a Set that contains the keys in this map. This method provides a set-view of the keys in this map.
Syntax:
public Set keySet()
Example
package com.w3schools; import java.util.HashMap; import java.util.Set; 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); //Get all keys Set<Integer> keys = hashMap.keySet(); for(Integer key: keys){ System.out.println(key); } } } |
Output
HashMap elements: {1=Munish, 2=Sunil, 3=Pardeep, 4=Roxy, 5=Sandy} 1 2 3 4 5 |