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	/*
	* Copyright (c) 2012, 2015, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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	/*
	* This file is available under and governed by the GNU General Public
	* License version 2 only, as published by the Free Software Foundation.
	* However, the following notice accompanied the original version of this
	* file:
	*
	* Copyright (c) 2007-2012, Stephen Colebourne & Michael Nascimento Santos
	*
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are met:
	*
	* * Redistributions of source code must retain the above copyright notice,
	* this list of conditions and the following disclaimer.
	*
	* * Redistributions in binary form must reproduce the above copyright notice,
	* this list of conditions and the following disclaimer in the documentation
	* and/or other materials provided with the distribution.
	*
	* * Neither the name of JSR-310 nor the names of its contributors
	* may be used to endorse or promote products derived from this software
	* without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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	* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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	package java.time;

	import java.io.DataOutput;
	import java.io.IOException;
	import java.io.InvalidObjectException;
	import java.io.ObjectInputStream;
	import java.io.Serializable;
	import java.time.format.DateTimeFormatterBuilder;
	import java.time.format.TextStyle;
	import java.time.temporal.TemporalAccessor;
	import java.time.temporal.TemporalField;
	import java.time.temporal.TemporalQueries;
	import java.time.temporal.TemporalQuery;
	import java.time.temporal.UnsupportedTemporalTypeException;
	import java.time.zone.ZoneRules;
	import java.time.zone.ZoneRulesException;
	import java.time.zone.ZoneRulesProvider;
	import java.util.Collections;
	import java.util.HashMap;
	import java.util.Locale;
	import java.util.Map;
	import java.util.Objects;
	import java.util.Set;
	import java.util.TimeZone;

	/**
	* A time-zone ID, such as {@code Europe/Paris}.
	* <p>
	* A {@code ZoneId} is used to identify the rules used to convert between
	* an {@link Instant} and a {@link LocalDateTime}.
	* There are two distinct types of ID:
	* <ul>
	* <li>Fixed offsets - a fully resolved offset from UTC/Greenwich, that uses
	* the same offset for all local date-times
	* <li>Geographical regions - an area where a specific set of rules for finding
	* the offset from UTC/Greenwich apply
	* </ul>
	* Most fixed offsets are represented by {@link ZoneOffset}.
	* Calling {@link #normalized()} on any {@code ZoneId} will ensure that a
	* fixed offset ID will be represented as a {@code ZoneOffset}.
	* <p>
	* The actual rules, describing when and how the offset changes, are defined by {@link ZoneRules}.
	* This class is simply an ID used to obtain the underlying rules.
	* This approach is taken because rules are defined by governments and change
	* frequently, whereas the ID is stable.
	* <p>
	* The distinction has other effects. Serializing the {@code ZoneId} will only send
	* the ID, whereas serializing the rules sends the entire data set.
	* Similarly, a comparison of two IDs only examines the ID, whereas
	* a comparison of two rules examines the entire data set.
	*
	* <h3>Time-zone IDs</h3>
	* The ID is unique within the system.
	* There are three types of ID.
	* <p>
	* The simplest type of ID is that from {@code ZoneOffset}.
	* This consists of 'Z' and IDs starting with '+' or '-'.
	* <p>
	* The next type of ID are offset-style IDs with some form of prefix,
	* such as 'GMT+2' or 'UTC+01:00'.
	* The recognised prefixes are 'UTC', 'GMT' and 'UT'.
	* The offset is the suffix and will be normalized during creation.
	* These IDs can be normalized to a {@code ZoneOffset} using {@code normalized()}.
	* <p>
	* The third type of ID are region-based IDs. A region-based ID must be of
	* two or more characters, and not start with 'UTC', 'GMT', 'UT' '+' or '-'.
	* Region-based IDs are defined by configuration, see {@link ZoneRulesProvider}.
	* The configuration focuses on providing the lookup from the ID to the
	* underlying {@code ZoneRules}.
	* <p>
	* Time-zone rules are defined by governments and change frequently.
	* There are a number of organizations, known here as groups, that monitor
	* time-zone changes and collate them.
	* The default group is the IANA Time Zone Database (TZDB).
	* Other organizations include IATA (the airline industry body) and Microsoft.
	* <p>
	* Each group defines its own format for the region ID it provides.
	* The TZDB group defines IDs such as 'Europe/London' or 'America/New_York'.
	* TZDB IDs take precedence over other groups.
	* <p>
	* It is strongly recommended that the group name is included in all IDs supplied by
	* groups other than TZDB to avoid conflicts. For example, IATA airline time-zone
	* region IDs are typically the same as the three letter airport code.
	* However, the airport of Utrecht has the code 'UTC', which is obviously a conflict.
	* The recommended format for region IDs from groups other than TZDB is 'group~region'.
	* Thus if IATA data were defined, Utrecht airport would be 'IATA~UTC'.
	*
	* <h3>Serialization</h3>
	* This class can be serialized and stores the string zone ID in the external form.
	* The {@code ZoneOffset} subclass uses a dedicated format that only stores the
	* offset from UTC/Greenwich.
	* <p>
	* A {@code ZoneId} can be deserialized in a Java Runtime where the ID is unknown.
	* For example, if a server-side Java Runtime has been updated with a new zone ID, but
	* the client-side Java Runtime has not been updated. In this case, the {@code ZoneId}
	* object will exist, and can be queried using {@code getId}, {@code equals},
	* {@code hashCode}, {@code toString}, {@code getDisplayName} and {@code normalized}.
	* However, any call to {@code getRules} will fail with {@code ZoneRulesException}.
	* This approach is designed to allow a {@link ZonedDateTime} to be loaded and
	* queried, but not modified, on a Java Runtime with incomplete time-zone information.
	*
	* <p>
	* This is a <a href="{@docRoot}/java/lang/doc-files/ValueBased.html">value-based</a>
	* class; use of identity-sensitive operations (including reference equality
	* ({@code ==}), identity hash code, or synchronization) on instances of
	* {@code ZoneId} may have unpredictable results and should be avoided.
	* The {@code equals} method should be used for comparisons.
	*
	* @implSpec
	* This abstract class has two implementations, both of which are immutable and thread-safe.
	* One implementation models region-based IDs, the other is {@code ZoneOffset} modelling
	* offset-based IDs. This difference is visible in serialization.
	*
	* @since 1.8
	*/
	public abstract class ZoneId implements Serializable {

	/**
	* A map of zone overrides to enable the short time-zone names to be used.
	* <p>
	* Use of short zone IDs has been deprecated in {@code java.util.TimeZone}.
	* This map allows the IDs to continue to be used via the
	* {@link #of(String, Map)} factory method.
	* <p>
	* This map contains a mapping of the IDs that is in line with TZDB 2005r and
	* later, where 'EST', 'MST' and 'HST' map to IDs which do not include daylight
	* savings.
	* <p>
	* This maps as follows:
	* <ul>
	* <li>EST - -05:00</li>
	* <li>HST - -10:00</li>
	* <li>MST - -07:00</li>
	* <li>ACT - Australia/Darwin</li>
	* <li>AET - Australia/Sydney</li>
	* <li>AGT - America/Argentina/Buenos_Aires</li>
	* <li>ART - Africa/Cairo</li>
	* <li>AST - America/Anchorage</li>
	* <li>BET - America/Sao_Paulo</li>
	* <li>BST - Asia/Dhaka</li>
	* <li>CAT - Africa/Harare</li>
	* <li>CNT - America/St_Johns</li>
	* <li>CST - America/Chicago</li>
	* <li>CTT - Asia/Shanghai</li>
	* <li>EAT - Africa/Addis_Ababa</li>
	* <li>ECT - Europe/Paris</li>
	* <li>IET - America/Indiana/Indianapolis</li>
	* <li>IST - Asia/Kolkata</li>
	* <li>JST - Asia/Tokyo</li>
	* <li>MIT - Pacific/Apia</li>
	* <li>NET - Asia/Yerevan</li>
	* <li>NST - Pacific/Auckland</li>
	* <li>PLT - Asia/Karachi</li>
	* <li>PNT - America/Phoenix</li>
	* <li>PRT - America/Puerto_Rico</li>
	* <li>PST - America/Los_Angeles</li>
	* <li>SST - Pacific/Guadalcanal</li>
	* <li>VST - Asia/Ho_Chi_Minh</li>
	* </ul>
	* The map is unmodifiable.
	*/
	public static final Map<String, String> SHORT_IDS;
	static {
	Map<String, String> map = new HashMap<>(64);
	map.put("ACT", "Australia/Darwin");
	map.put("AET", "Australia/Sydney");
	map.put("AGT", "America/Argentina/Buenos_Aires");
	map.put("ART", "Africa/Cairo");
	map.put("AST", "America/Anchorage");
	map.put("BET", "America/Sao_Paulo");
	map.put("BST", "Asia/Dhaka");
	map.put("CAT", "Africa/Harare");
	map.put("CNT", "America/St_Johns");
	map.put("CST", "America/Chicago");
	map.put("CTT", "Asia/Shanghai");
	map.put("EAT", "Africa/Addis_Ababa");
	map.put("ECT", "Europe/Paris");
	map.put("IET", "America/Indiana/Indianapolis");
	map.put("IST", "Asia/Kolkata");
	map.put("JST", "Asia/Tokyo");
	map.put("MIT", "Pacific/Apia");
	map.put("NET", "Asia/Yerevan");
	map.put("NST", "Pacific/Auckland");
	map.put("PLT", "Asia/Karachi");
	map.put("PNT", "America/Phoenix");
	map.put("PRT", "America/Puerto_Rico");
	map.put("PST", "America/Los_Angeles");
	map.put("SST", "Pacific/Guadalcanal");
	map.put("VST", "Asia/Ho_Chi_Minh");
	map.put("EST", "-05:00");
	map.put("MST", "-07:00");
	map.put("HST", "-10:00");
	SHORT_IDS = Collections.unmodifiableMap(map);
	}
	/**
	* Serialization version.
	*/
	private static final long serialVersionUID = 8352817235686L;

	//-----------------------------------------------------------------------
	/**
	* Gets the system default time-zone.
	* <p>
	* This queries {@link TimeZone#getDefault()} to find the default time-zone
	* and converts it to a {@code ZoneId}. If the system default time-zone is changed,
	* then the result of this method will also change.
	*
	* @return the zone ID, not null
	* @throws DateTimeException if the converted zone ID has an invalid format
	* @throws ZoneRulesException if the converted zone region ID cannot be found
	*/
	public static ZoneId systemDefault() {
	return TimeZone.getDefault().toZoneId();
	}

	/**
	* Gets the set of available zone IDs.
	* <p>
	* This set includes the string form of all available region-based IDs.
	* Offset-based zone IDs are not included in the returned set.
	* The ID can be passed to {@link #of(String)} to create a {@code ZoneId}.
	* <p>
	* The set of zone IDs can increase over time, although in a typical application
	* the set of IDs is fixed. Each call to this method is thread-safe.
	*
	* @return a modifiable copy of the set of zone IDs, not null
	*/
	public static Set<String> getAvailableZoneIds() {
	return ZoneRulesProvider.getAvailableZoneIds();
	}

	//-----------------------------------------------------------------------
	/**
	* Obtains an instance of {@code ZoneId} using its ID using a map
	* of aliases to supplement the standard zone IDs.
	* <p>
	* Many users of time-zones use short abbreviations, such as PST for
	* 'Pacific Standard Time' and PDT for 'Pacific Daylight Time'.
	* These abbreviations are not unique, and so cannot be used as IDs.
	* This method allows a map of string to time-zone to be setup and reused
	* within an application.
	*
	* @param zoneId the time-zone ID, not null
	* @param aliasMap a map of alias zone IDs (typically abbreviations) to real zone IDs, not null
	* @return the zone ID, not null
	* @throws DateTimeException if the zone ID has an invalid format
	* @throws ZoneRulesException if the zone ID is a region ID that cannot be found
	*/
	public static ZoneId of(String zoneId, Map<String, String> aliasMap) {
	Objects.requireNonNull(zoneId, "zoneId");
	Objects.requireNonNull(aliasMap, "aliasMap");
	String id = aliasMap.get(zoneId);
	id = (id != null ? id : zoneId);
	return of(id);
	}

	/**
	* Obtains an instance of {@code ZoneId} from an ID ensuring that the
	* ID is valid and available for use.
	* <p>
	* This method parses the ID producing a {@code ZoneId} or {@code ZoneOffset}.
	* A {@code ZoneOffset} is returned if the ID is 'Z', or starts with '+' or '-'.
	* The result will always be a valid ID for which {@link ZoneRules} can be obtained.
	* <p>
	* Parsing matches the zone ID step by step as follows.
	* <ul>
	* <li>If the zone ID equals 'Z', the result is {@code ZoneOffset.UTC}.
	* <li>If the zone ID consists of a single letter, the zone ID is invalid
	* and {@code DateTimeException} is thrown.
	* <li>If the zone ID starts with '+' or '-', the ID is parsed as a
	* {@code ZoneOffset} using {@link ZoneOffset#of(String)}.
	* <li>If the zone ID equals 'GMT', 'UTC' or 'UT' then the result is a {@code ZoneId}
	* with the same ID and rules equivalent to {@code ZoneOffset.UTC}.
	* <li>If the zone ID starts with 'UTC+', 'UTC-', 'GMT+', 'GMT-', 'UT+' or 'UT-'
	* then the ID is a prefixed offset-based ID. The ID is split in two, with
	* a two or three letter prefix and a suffix starting with the sign.
	* The suffix is parsed as a {@link ZoneOffset#of(String) ZoneOffset}.
	* The result will be a {@code ZoneId} with the specified UTC/GMT/UT prefix
	* and the normalized offset ID as per {@link ZoneOffset#getId()}.
	* The rules of the returned {@code ZoneId} will be equivalent to the
	* parsed {@code ZoneOffset}.
	* <li>All other IDs are parsed as region-based zone IDs. Region IDs must
	* match the regular expression <code>[A-Za-z][A-Za-z0-9~/._+-]+</code>
	* otherwise a {@code DateTimeException} is thrown. If the zone ID is not
	* in the configured set of IDs, {@code ZoneRulesException} is thrown.
	* The detailed format of the region ID depends on the group supplying the data.
	* The default set of data is supplied by the IANA Time Zone Database (TZDB).
	* This has region IDs of the form '{area}/{city}', such as 'Europe/Paris' or 'America/New_York'.
	* This is compatible with most IDs from {@link java.util.TimeZone}.
	* </ul>
	*
	* @param zoneId the time-zone ID, not null
	* @return the zone ID, not null
	* @throws DateTimeException if the zone ID has an invalid format
	* @throws ZoneRulesException if the zone ID is a region ID that cannot be found
	*/
	public static ZoneId of(String zoneId) {
	return of(zoneId, true);
	}

	/**
	* Obtains an instance of {@code ZoneId} wrapping an offset.
	* <p>
	* If the prefix is "GMT", "UTC", or "UT" a {@code ZoneId}
	* with the prefix and the non-zero offset is returned.
	* If the prefix is empty {@code ""} the {@code ZoneOffset} is returned.
	*
	* @param prefix the time-zone ID, not null
	* @param offset the offset, not null
	* @return the zone ID, not null
	* @throws IllegalArgumentException if the prefix is not one of
	* "GMT", "UTC", or "UT", or ""
	*/
	public static ZoneId ofOffset(String prefix, ZoneOffset offset) {
	Objects.requireNonNull(prefix, "prefix");
	Objects.requireNonNull(offset, "offset");
	if (prefix.length() == 0) {
	return offset;
	}

	if (!prefix.equals("GMT") && !prefix.equals("UTC") && !prefix.equals("UT")) {
	throw new IllegalArgumentException("prefix should be GMT, UTC or UT, is: " + prefix);
	}

	if (offset.getTotalSeconds() != 0) {
	prefix = prefix.concat(offset.getId());
	}
	return new ZoneRegion(prefix, offset.getRules());
	}

	/**
	* Parses the ID, taking a flag to indicate whether {@code ZoneRulesException}
	* should be thrown or not, used in deserialization.
	*
	* @param zoneId the time-zone ID, not null
	* @param checkAvailable whether to check if the zone ID is available
	* @return the zone ID, not null
	* @throws DateTimeException if the ID format is invalid
	* @throws ZoneRulesException if checking availability and the ID cannot be found
	*/
	static ZoneId of(String zoneId, boolean checkAvailable) {
	Objects.requireNonNull(zoneId, "zoneId");
	if (zoneId.length() <= 1 \|\| zoneId.startsWith("+") \|\| zoneId.startsWith("-")) {
	return ZoneOffset.of(zoneId);
	} else if (zoneId.startsWith("UTC") \|\| zoneId.startsWith("GMT")) {
	return ofWithPrefix(zoneId, 3, checkAvailable);
	} else if (zoneId.startsWith("UT")) {
	return ofWithPrefix(zoneId, 2, checkAvailable);
	}
	return ZoneRegion.ofId(zoneId, checkAvailable);
	}

	/**
	* Parse once a prefix is established.
	*
	* @param zoneId the time-zone ID, not null
	* @param prefixLength the length of the prefix, 2 or 3
	* @return the zone ID, not null
	* @throws DateTimeException if the zone ID has an invalid format
	*/
	private static ZoneId ofWithPrefix(String zoneId, int prefixLength, boolean checkAvailable) {
	String prefix = zoneId.substring(0, prefixLength);
	if (zoneId.length() == prefixLength) {
	return ofOffset(prefix, ZoneOffset.UTC);
	}
	if (zoneId.charAt(prefixLength) != '+' && zoneId.charAt(prefixLength) != '-') {
	return ZoneRegion.ofId(zoneId, checkAvailable); // drop through to ZoneRulesProvider
	}
	try {
	ZoneOffset offset = ZoneOffset.of(zoneId.substring(prefixLength));
	if (offset == ZoneOffset.UTC) {
	return ofOffset(prefix, offset);
	}
	return ofOffset(prefix, offset);
	} catch (DateTimeException ex) {
	throw new DateTimeException("Invalid ID for offset-based ZoneId: " + zoneId, ex);
	}
	}

	//-----------------------------------------------------------------------
	/**
	* Obtains an instance of {@code ZoneId} from a temporal object.
	* <p>
	* This obtains a zone based on the specified temporal.
	* A {@code TemporalAccessor} represents an arbitrary set of date and time information,
	* which this factory converts to an instance of {@code ZoneId}.
	* <p>
	* A {@code TemporalAccessor} represents some form of date and time information.
	* This factory converts the arbitrary temporal object to an instance of {@code ZoneId}.
	* <p>
	* The conversion will try to obtain the zone in a way that favours region-based
	* zones over offset-based zones using {@link TemporalQueries#zone()}.
	* <p>
	* This method matches the signature of the functional interface {@link TemporalQuery}
	* allowing it to be used as a query via method reference, {@code ZoneId::from}.
	*
	* @param temporal the temporal object to convert, not null
	* @return the zone ID, not null
	* @throws DateTimeException if unable to convert to a {@code ZoneId}
	*/
	public static ZoneId from(TemporalAccessor temporal) {
	ZoneId obj = temporal.query(TemporalQueries.zone());
	if (obj == null) {
	throw new DateTimeException("Unable to obtain ZoneId from TemporalAccessor: " +
	temporal + " of type " + temporal.getClass().getName());
	}
	return obj;
	}

	//-----------------------------------------------------------------------
	/**
	* Constructor only accessible within the package.
	*/
	ZoneId() {
	if (getClass() != ZoneOffset.class && getClass() != ZoneRegion.class) {
	throw new AssertionError("Invalid subclass");
	}
	}

	//-----------------------------------------------------------------------
	/**
	* Gets the unique time-zone ID.
	* <p>
	* This ID uniquely defines this object.
	* The format of an offset based ID is defined by {@link ZoneOffset#getId()}.
	*
	* @return the time-zone unique ID, not null
	*/
	public abstract String getId();

	//-----------------------------------------------------------------------
	/**
	* Gets the textual representation of the zone, such as 'British Time' or
	* '+02:00'.
	* <p>
	* This returns the textual name used to identify the time-zone ID,
	* suitable for presentation to the user.
	* The parameters control the style of the returned text and the locale.
	* <p>
	* If no textual mapping is found then the {@link #getId() full ID} is returned.
	*
	* @param style the length of the text required, not null
	* @param locale the locale to use, not null
	* @return the text value of the zone, not null
	*/
	public String getDisplayName(TextStyle style, Locale locale) {
	return new DateTimeFormatterBuilder().appendZoneText(style).toFormatter(locale).format(toTemporal());
	}

	/**
	* Converts this zone to a {@code TemporalAccessor}.
	* <p>
	* A {@code ZoneId} can be fully represented as a {@code TemporalAccessor}.
	* However, the interface is not implemented by this class as most of the
	* methods on the interface have no meaning to {@code ZoneId}.
	* <p>
	* The returned temporal has no supported fields, with the query method
	* supporting the return of the zone using {@link TemporalQueries#zoneId()}.
	*
	* @return a temporal equivalent to this zone, not null
	*/
	private TemporalAccessor toTemporal() {
	return new TemporalAccessor() {
	@Override
	public boolean isSupported(TemporalField field) {
	return false;
	}
	@Override
	public long getLong(TemporalField field) {
	throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
	}
	@SuppressWarnings("unchecked")
	@Override
	public <R> R query(TemporalQuery<R> query) {
	if (query == TemporalQueries.zoneId()) {
	return (R) ZoneId.this;
	}
	return TemporalAccessor.super.query(query);
	}
	};
	}

	//-----------------------------------------------------------------------
	/**
	* Gets the time-zone rules for this ID allowing calculations to be performed.
	* <p>
	* The rules provide the functionality associated with a time-zone,
	* such as finding the offset for a given instant or local date-time.
	* <p>
	* A time-zone can be invalid if it is deserialized in a Java Runtime which
	* does not have the same rules loaded as the Java Runtime that stored it.
	* In this case, calling this method will throw a {@code ZoneRulesException}.
	* <p>
	* The rules are supplied by {@link ZoneRulesProvider}. An advanced provider may
	* support dynamic updates to the rules without restarting the Java Runtime.
	* If so, then the result of this method may change over time.
	* Each individual call will be still remain thread-safe.
	* <p>
	* {@link ZoneOffset} will always return a set of rules where the offset never changes.
	*
	* @return the rules, not null
	* @throws ZoneRulesException if no rules are available for this ID
	*/
	public abstract ZoneRules getRules();

	/**
	* Normalizes the time-zone ID, returning a {@code ZoneOffset} where possible.
	* <p>
	* The returns a normalized {@code ZoneId} that can be used in place of this ID.
	* The result will have {@code ZoneRules} equivalent to those returned by this object,
	* however the ID returned by {@code getId()} may be different.
	* <p>
	* The normalization checks if the rules of this {@code ZoneId} have a fixed offset.
	* If they do, then the {@code ZoneOffset} equal to that offset is returned.
	* Otherwise {@code this} is returned.
	*
	* @return the time-zone unique ID, not null
	*/
	public ZoneId normalized() {
	try {
	ZoneRules rules = getRules();
	if (rules.isFixedOffset()) {
	return rules.getOffset(Instant.EPOCH);
	}
	} catch (ZoneRulesException ex) {
	// invalid ZoneRegion is not important to this method
	}
	return this;
	}

	//-----------------------------------------------------------------------
	/**
	* Checks if this time-zone ID is equal to another time-zone ID.
	* <p>
	* The comparison is based on the ID.
	*
	* @param obj the object to check, null returns false
	* @return true if this is equal to the other time-zone ID
	*/
	@Override
	public boolean equals(Object obj) {
	if (this == obj) {
	return true;
	}
	if (obj instanceof ZoneId) {
	ZoneId other = (ZoneId) obj;
	return getId().equals(other.getId());
	}
	return false;
	}

	/**
	* A hash code for this time-zone ID.
	*
	* @return a suitable hash code
	*/
	@Override
	public int hashCode() {
	return getId().hashCode();
	}

	//-----------------------------------------------------------------------
	/**
	* Defend against malicious streams.
	*
	* @param s the stream to read
	* @throws InvalidObjectException always
	*/
	private void readObject(ObjectInputStream s) throws InvalidObjectException {
	throw new InvalidObjectException("Deserialization via serialization delegate");
	}

	/**
	* Outputs this zone as a {@code String}, using the ID.
	*
	* @return a string representation of this time-zone ID, not null
	*/
	@Override
	public String toString() {
	return getId();
	}

	//-----------------------------------------------------------------------
	/**
	* Writes the object using a
	* <a href="../../serialized-form.html#java.time.Ser">dedicated serialized form</a>.
	* @serialData
	* <pre>
	* out.writeByte(7); // identifies a ZoneId (not ZoneOffset)
	* out.writeUTF(getId());
	* </pre>
	* <p>
	* When read back in, the {@code ZoneId} will be created as though using
	* {@link #of(String)}, but without any exception in the case where the
	* ID has a valid format, but is not in the known set of region-based IDs.
	*
	* @return the instance of {@code Ser}, not null
	*/
	// this is here for serialization Javadoc
	private Object writeReplace() {
	return new Ser(Ser.ZONE_REGION_TYPE, this);
	}

	abstract void write(DataOutput out) throws IOException;

	}

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