Java tutorial
//package com.java2s; import java.util.HashMap; import java.util.Iterator; import java.util.Map; import java.util.Set; public class Main { @SuppressWarnings("rawtypes") public static Map<Integer, String> swapStrKeysAndIntValues(Map<String, Integer> hm) { HashMap<Integer, String> nhm = new HashMap<Integer, String>(); Set<?> s = hm.entrySet(); Iterator<?> it = s.iterator(); while (it.hasNext()) { Map.Entry m = (Map.Entry) it.next(); nhm.put((Integer) m.getValue(), (String) m.getKey()); } return nhm; } }