import java.time.Instant;
import java.time.LocalDate;
import java.time.ZoneId;
 
public class Main {
    public static void main(String[] args) {
        long timestampDate = 1623307684L;
        Instant instant = Instant.ofEpochSecond(timestampDate);
 
        // Replace JVM's timezone, ZoneId.systemDefault() with the applicable timezone
        // e.g. ZoneId.of("Etc/UTC")
        LocalDate date = instant.atZone(ZoneId.systemDefault()).toLocalDate();
        LocalDate today = LocalDate.now(ZoneId.systemDefault());
        if (date.isBefore(today)) {
            System.out.println("The given timestamp is for a date in the past.");
            // ...
        }
 
        if (date.equals(today.minusDays(1))) {
            System.out.println("Yesterday");
        }
    }
}
 

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