Asia/Tokyo2020

ZoneTokyo2020Register.java

import java.time.LocalDateTime;
import java.time.Month;
import java.time.ZoneOffset;
import java.time.zone.ZoneOffsetTransition;
import java.time.zone.ZoneOffsetTransitionRule;
import java.time.zone.ZoneRules;
import java.time.zone.ZoneRulesProvider;
import java.util.*;

public class ZoneTokyo2020Register {
    static {
        List<ZoneOffsetTransition> standardTransitions = new ArrayList<>();
        standardTransitions.add(ZoneOffsetTransition.of(LocalDateTime.of(1887, Month.DECEMBER, 31, 15, 18, 59), ZoneOffset.of("+09:18:59"), ZoneOffset.of("+09:00")));
        List<ZoneOffsetTransition> transitions = new ArrayList<>();
        transitions.add(ZoneOffsetTransition.of(LocalDateTime.of(1888, Month.JANUARY, 1, 0, 18, 59), ZoneOffset.of("+09:18:59"), ZoneOffset.of("+09:00")));
        transitions.add(ZoneOffsetTransition.of(LocalDateTime.of(1948, Month.MAY, 2, 0, 0), ZoneOffset.of("+09:00"), ZoneOffset.of("+10:00")));
        transitions.add(ZoneOffsetTransition.of(LocalDateTime.of(1948, Month.SEPTEMBER, 12, 0, 0), ZoneOffset.of("+10:00"), ZoneOffset.of("+09:00")));
        transitions.add(ZoneOffsetTransition.of(LocalDateTime.of(1949, Month.APRIL, 3, 0, 0), ZoneOffset.of("+09:00"), ZoneOffset.of("+10:00")));
        transitions.add(ZoneOffsetTransition.of(LocalDateTime.of(1949, Month.SEPTEMBER, 11, 0, 0), ZoneOffset.of("+10:00"), ZoneOffset.of("+09:00")));
        transitions.add(ZoneOffsetTransition.of(LocalDateTime.of(1950, Month.MAY, 7, 0, 0), ZoneOffset.of("+09:00"), ZoneOffset.of("+10:00")));
        transitions.add(ZoneOffsetTransition.of(LocalDateTime.of(1950, Month.SEPTEMBER, 10, 0, 0), ZoneOffset.of("+10:00"), ZoneOffset.of("+09:00")));
        transitions.add(ZoneOffsetTransition.of(LocalDateTime.of(1951, Month.MAY, 6, 0, 0), ZoneOffset.of("+09:00"), ZoneOffset.of("+10:00")));
        transitions.add(ZoneOffsetTransition.of(LocalDateTime.of(1951, Month.SEPTEMBER, 9, 0, 0), ZoneOffset.of("+10:00"), ZoneOffset.of("+09:00")));

        // For the Tokyo Olympic
        transitions.add(ZoneOffsetTransition.of(LocalDateTime.of(2019, Month.JUNE, 1, 0, 0), ZoneOffset.of("+09:00"), ZoneOffset.of("+11:00")));
        transitions.add(ZoneOffsetTransition.of(LocalDateTime.of(2019, Month.SEPTEMBER, 1, 0, 0), ZoneOffset.of("+11:00"), ZoneOffset.of("+09:00")));
        transitions.add(ZoneOffsetTransition.of(LocalDateTime.of(2020, Month.JUNE, 1, 0, 0), ZoneOffset.of("+09:00"), ZoneOffset.of("+11:00")));
        transitions.add(ZoneOffsetTransition.of(LocalDateTime.of(2020, Month.SEPTEMBER, 1, 0, 0), ZoneOffset.of("+11:00"), ZoneOffset.of("+09:00")));

        List<ZoneOffsetTransitionRule> rules = new ArrayList<>();
        ZoneRules tokyo2020 = ZoneRules.of(ZoneOffset.of("+09:18:59"), ZoneOffset.of("+09:18:59"),
                standardTransitions, transitions, rules);
        ZoneRulesProvider.registerProvider(new ZoneRulesProvider() {
            private Set<String> ids = new HashSet<>(Arrays.asList("Asia/Tokyo2020"));

            @Override
            protected Set<String> provideZoneIds() {
                return ids;
            }

            @Override
            protected ZoneRules provideRules(String zoneId, boolean forCaching) {
                if (zoneId.equals("Asia/Tokyo2020")) {
                    return tokyo2020;
                }
                return null;
            }

            @Override
            protected NavigableMap<String, ZoneRules> provideVersions(String zoneId) {
                NavigableMap<String, ZoneRules> versions = new TreeMap<>();
                versions.put("2018e", tokyo2020); // I think this is a wrong version
                return versions;
            }
        });
    }
}

ZoneTokyo2020Test.java

public class ZoneTokyo2020Test {
    @Before
    public void setup() throws ClassNotFoundException {
        Class.forName("ZoneTokyo2020Register");
    }

    @Test
    public void test() {
        DateTimeFormatter format = DateTimeFormatter
                .ofPattern("yyyy/MMM/d a hh:mm Z");
        ZoneId tokyo = ZoneId.of("Asia/Tokyo2020");
        System.out.println(ZonedDateTime.of(LocalDateTime.of(2018, Month.MAY, 31, 23, 59), tokyo).format(format));
        System.out.println(ZonedDateTime.of(LocalDateTime.of(2018, Month.JUNE, 1, 0, 0), tokyo).format(format));
        System.out.println(ZonedDateTime.of(LocalDateTime.of(2019, Month.MAY, 31, 23, 59), tokyo).format(format));
        System.out.println(ZonedDateTime.of(LocalDateTime.of(2019, Month.JUNE, 1, 0, 0), tokyo).format(format));
        System.out.println(ZonedDateTime.of(LocalDateTime.of(2019, Month.AUGUST, 31, 23, 59), tokyo).format(format));
        System.out.println(ZonedDateTime.of(LocalDateTime.of(2019, Month.SEPTEMBER, 1, 0, 0), tokyo).format(format));
    }
}