public class Main {
public static Map<String, String> usersMap = new LinkedHashMap<String, String>() {{
put("Иванов", "Иван");
put("Пупкин", "Вася");
put("Коваленко", "Петя");
put("Лубнов", "Иван");
}};
public static void main(String[] args) {
Set<String> names = new HashSet<String>();
for (Iterator<Map.Entry<String, String>> iterator = usersMap.entrySet().iterator(); iterator.hasNext(); ) {
Map.Entry<String, String> next = iterator.next();
if (names.contains(next.getValue())) {
iterator.remove();
} else {
names.add(next.getValue());
}
}
System.out.println(usersMap);
}
}