Java tutorial
//package com.java2s; //License from project: BSD License import java.util.Map; import java.util.Map.Entry; public class Main { public static <T, E> T getKeyByValue(Map<T, E> map, E value) { if (map == null) { return null; } for (Entry<T, E> entry : map.entrySet()) { if (entry.getValue().equals(value)) { return entry.getKey(); } } return null; } }