hashmap get key from value code example

Example 1: java map get the key from value

public static <T, E> Set<T> getKeyByValue(Map<T, E> map, E value) {
    return map.entrySet()
              .stream()
              .filter(entry -> Objects.equals(entry.getValue(), value))
              .map(Map.Entry::getKey)
              .collect(Collectors.toSet());
}

Example 2: hashmap get value by key java

import java.util.HashMap;
//Within a class
//You can do new HashMap<Key Type, Value Type>();, but you don't need to
HashMap<Int, String> examplehashmap=new HashMap<>();
{
//put in values
 examplehashmap.put(5, "example");
};
//get value
examplehashmap.get(5);
//returns "example"

Example 3: java hashmap get value

package com.tutorialspoint;

import java.util.*;

public class HashMapDemo {
   public static void main(String args[]) {
      
      // create hash map
      HashMap newmap = new HashMap();

      // populate hash map
      newmap.put(1, "tutorials");
      newmap.put(2, "point");
      newmap.put(3, "is best");

      // get value of key 3
      String val = (String)newmap.get(3);

      // check the value
      System.out.println("Value for key 3 is: " + val);
   }    
}