[Java] distinct by property

public static <T> Predicate<T> distinctByKey(Function<? super T, ?> keyExtractor) {
    Set<Object> seen = ConcurrentHashMap.newKeySet();
    return t -> seen.add(keyExtractor.apply(t));
}

https://stackoverflow.com/questions/23699371/java-8-distinct-by-property

Java 8 Distinct by property