import java.time.LocalDate;
import java.util.List;
import java.util.stream.Collectors;

public class Main {
	public static void main(String[] args) {
		List<String> dates = List.of("2012-05-16", "2012-05-18", "2012-06-19", 
				"2013-01-18", "2013-01-10", "2013-08-05",	"2010-07-10");

        List<String> yearsStrList =
        		dates.stream()
	                .map(LocalDate::parse)
	                .map(d -> String.valueOf(d.getYear()))
	                .distinct()
	                .collect(Collectors.toList());

		System.out.println(yearsStrList);
	}
}