Java Local Date Time

import java.time.Duration;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.time.temporal.ChronoUnit;

class Playground {
    public static void main(String[ ] args) {
        DateTimeFormatter format = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS");
        LocalDateTime    endDate = LocalDateTime.now().truncatedTo(ChronoUnit.DAYS).plusHours(23).minusNanos(1L);
        LocalDateTime  startDate = endDate.minusDays(1).plusNanos(1L);

        System.out.println("Start Date: " + startDate.format(format));
        System.out.println("end   Date: " +   endDate.format(format));
    }
}

References

Java Playground Online