source: PerfectFit/Dialog/src/test/java/movingdialog/dateParseTest.java

package movingdialog;

import java.text.ParseException;
import java.time.LocalDate;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;

import org.junit.Ignore;
import org.junit.Test;

public class dateParseTest {
//      LocalDate date1 = LocalDate.of(2021, 12, 17); // dec 17 2021
//      LocalDate date2 = LocalDate.of(2021, 1, 7); // jan 7

        @Test
        public void parseDateTest1() throws ParseException {
                System.out.println(getSeconds("17 12 2021", "d M y"));
                System.out.println(getSeconds("7 1 2021", "d M y"));
                System.out.println(getSeconds("7 1 21", "d M y"));
        }

        @Test
        public void parseDateTest2() throws ParseException {
                System.out.println(getSeconds("17-12-2021", "d-M-y"));
                System.out.println(getSeconds("7-1-2021", "d-M-y"));
                System.out.println(getSeconds("7-1-21", "d-M-y"));
        }

        /**
         * Maybe if we can figure out how this parser pareses NAMES of month...
         */
        @Ignore
        @Test
        public void parseDateTest3() throws ParseException {
                System.out.println(getSeconds("17 dec 2021", "d LLL y"));
        }

        private double getSeconds(String date, String format) {
                DateTimeFormatter formatter = DateTimeFormatter.ofPattern(format);

                return LocalDate.parse(date, formatter)
                                .atStartOfDay(ZoneId.systemDefault()).toInstant().toEpochMilli()
                                / 1000d;

        }
}