extractDates.java

import java.util.List;
import java.util.ArrayList;
import java.util.Set;
import java.util.HashSet;
import java.time.LocalDate;
import java.util.regex.Pattern;
import java.util.regex.Matcher;
import java.time.DateTimeException;


public class MyClass {
    public static void main(String args[]) {
      
      
      List<LocalDate> dates = extractDates("auhz uazhd a29-02-2023zz   r29-02-2024z  8-02-2024");
      
      System.out.println(dates);

      int uniqueYears = countUniqueYears("auhz uazhd a29-02-2023zz   r29-02-2024z  8-02-2024");
      System.out.println(uniqueYears);

    }

    public static int countUniqueYears(String inputStr) {
         List<LocalDate> dates = extractDates(inputStr);
         Set uniqueDates = new HashSet<Integer>();
         
         dates.forEach((d) -> uniqueDates.add(d.getYear()));
         return uniqueDates.size();
    }
    
    public static List<LocalDate> extractDates(String inputStr) {
        List<LocalDate> result = new ArrayList<LocalDate>();
        
        Pattern pattern = Pattern.compile("(\\d{1,2})-(\\d{1,2})-(\\d{2,4})");
        Matcher matcher = pattern.matcher(inputStr);
        while (matcher.find()) {
            String day = matcher.group(1);
            String month = matcher.group(2);
            String year = matcher.group(3);
            try {
                result.add(LocalDate.of(Integer.parseInt(year), Integer.parseInt(month), Integer.parseInt(day)));
            }
            catch (DateTimeException exception) {
                // ignore bad dates 
            }
        }
        return result;

    }

}