Answer by Shashank Bodkhe for Java Hashmap: How to get key from value?

Simplest utility method to fetch a key of a given value from a Map:

public static void fetchValue(Map<String, Integer> map, Integer i){   Stream stream = map.entrySet().stream().filter(val-> val.getValue().equals(i)).map(Map.Entry::getKey);stream.forEach(System.out::println);    }

detailed explaination:

1. Method fetchValue accepts the map, which has String as key and Integer as value.

2. Then we use entryset().stream() to convert result into a stream.

3. Next we use filter (intermediate operation) which gives us a value that is equal to the second argument.

4. Finally, we use forEach(final operation) to print our end result.