import java.sql.Timestamp;
import java.time.Instant;
import java.time.temporal.ChronoUnit;
import java.util.Optional;
 
class Ideone {
 
    public static void main (String[] args) {
        Timestamp timestamp = Timestamp.from(Instant.now());
        System.out.println(timestamp);
        Optional.of(timestamp)
                .map(Timestamp::toInstant)
                .map(t -> t.minus(21, ChronoUnit.DAYS))
                .map(Timestamp::from)
                .ifPresent(System.out::println);
 
 
    }
}

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