Strict Date Parsing

Strict Date Parsing

Save as Main.java and run with a Java 17+ JDK: java Main.java.

import java.time.LocalDate;
import java.time.format.*;

public class Main {
  public static void main(String[] args) throws Exception {
    DateTimeFormatter format = DateTimeFormatter.ofPattern("dd/MM/uuuu")
        .withResolverStyle(ResolverStyle.STRICT);
    System.out.println(LocalDate.parse("29/02/2024", format));
    try {
      LocalDate.parse("29/02/2023", format);
    } catch (DateTimeParseException ex) {
      System.out.println("invalid date");
    }
  }
}

1. Expected output: 2024-02-29 invalid date
2. uuuu represents the proleptic year needed here without a separate era. Strict parsing rejects February 29 in a non-leap year.