OpenJDK 27 · java.time.ZoneId · APIdia, the JavaDoc alternative

A time-zone ID, such as Europe/Paris.

A ZoneId is used to identify the rules used to convert between an Instant and a LocalDateTime. There are two distinct types of ID:

Fixed offsets - a fully resolved offset from UTC/Greenwich, that uses the same offset for all local date-times
Geographical regions - an area where a specific set of rules for finding the offset from UTC/Greenwich apply

Most fixed offsets are represented by ZoneOffset. Calling normalized() on any ZoneId will ensure that a fixed offset ID will be represented as a ZoneOffset.

The actual rules, describing when and how the offset changes, are defined by 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.

The distinction has other effects. Serializing the 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.

Time-zone IDs

The ID is unique within the system. There are three types of ID.

The simplest type of ID is that from ZoneOffset. This consists of 'Z' and IDs starting with '+' or '-'.

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 ZoneOffset using normalized().

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 ZoneRulesProvider. The configuration focuses on providing the lookup from the ID to the underlying ZoneRules.

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.

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.

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'.

Serialization

This class can be serialized and stores the string zone ID in the external form. The ZoneOffset subclass uses a dedicated format that only stores the offset from UTC/Greenwich.

A 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 ZoneId object will exist, and can be queried using getId, equals, hashCode, toString, getDisplayName and normalized. However, any call to getRules will fail with ZoneRulesException. This approach is designed to allow a ZonedDateTime to be loaded and queried, but not modified, on a Java Runtime with incomplete time-zone information.

This is a value-based class; programmers should treat instances that are equal as interchangeable and should not use instances for synchronization, or unpredictable behavior may occur. For example, in a future release, synchronization may fail. The equals method should be used for comparisons.

Field Summary

Modifier and Type	Field and Description
private static final long	serialVersionUID Serialization version.
public static final Map<String, String>	SHORT_IDS A map of zone overrides to enable the short time-zone names to be used.

Constructor Summary

Access	Constructor and Description
pack-priv	ZoneId() Constructor only accessible within the package.

Method Summary

Modifier and Type	Method and Description
public boolean	Returns: true if this is equal to the other time-zone ID equals(Object the object to check, null returns false obj) Overrides java.lang.Object.equals. Checks if this time-zone ID is equal to another time-zone ID. The comparison is based on the ID.
public static ZoneId	Returns: the zone ID, not null from(TemporalAccessor the temporal object to convert, not null temporal) Obtains an instance of `ZoneId` from a temporal object.
public static Set<String>	Returns: a modifiable copy of the set of zone IDs, not null getAvailableZoneIds() Gets the set of available zone IDs.
public String	Returns: the text value of the zone, not null getDisplayName(TextStyle the length of the text required, not null style, Locale the locale to use, not null locale) Gets the textual representation of the zone, such as 'British Time' or '+02:00'.
public abstract String	Returns: the time-zone unique ID, not null getId() Gets the unique time-zone ID. This ID uniquely defines this object.
pack-priv abstract ZoneOffset	getOffset(long epochSecond) Get the effective offset for an instant at the given epochSecond.
public abstract ZoneRules	Returns: the rules, not null getRules() Gets the time-zone rules for this ID allowing calculations to be performed.
public int	Returns: a suitable hash code hashCode() Overrides java.lang.Object.hashCode. A hash code for this time-zone ID.
public ZoneId	Returns: the time-zone unique ID, not null normalized() Normalizes the time-zone ID, returning a `ZoneOffset` where possible.
public static ZoneId	Returns: the zone ID, not null of(String the time-zone ID, not null zoneId, Map<String, String> a map of alias zone IDs (typically abbreviations) to real zone IDs, not null aliasMap) Obtains an instance of `ZoneId` using its ID using a map of aliases to supplement the standard zone IDs.
public static ZoneId	Returns: the zone ID, not null of(String the time-zone ID, not null zoneId) Obtains an instance of `ZoneId` from an ID ensuring that the ID is valid and available for use.
pack-priv static ZoneId	Returns: the zone ID, not null of(String the time-zone ID, not null zoneId, boolean whether to check if the zone ID is available checkAvailable) Parses the ID, taking a flag to indicate whether `ZoneRulesException` should be thrown or not, used in deserialization.
public static ZoneId	Returns: the zone ID, not null ofOffset(String the time-zone ID, not null prefix, ZoneOffset the offset, not null offset) Obtains an instance of `ZoneId` wrapping an offset.
private static ZoneId	Returns: the zone ID, not null ofWithPrefix(String the time-zone ID, not null zoneId, int the length of the prefix, 2 or 3 prefixLength, boolean checkAvailable) Parse once a prefix is established.
private void	readObject(ObjectInputStream the stream to read s) Defend against malicious streams.
public static ZoneId	Returns: the zone ID, not null systemDefault() Gets the system default time-zone.
public String	Returns: a string representation of this time-zone ID, not null toString() Overrides java.lang.Object.toString. Outputs this zone as a `String`, using the ID.
private TemporalAccessor	Returns: a temporal equivalent to this zone, not null toTemporal() Converts this zone to a `TemporalAccessor`.
pack-priv abstract void	write(DataOutput out)
private Object	Returns: the instance of `Ser`, not null writeReplace() Writes the object using a dedicated serialized form.

Inherited from java.lang.Object:: clone finalize getClass notify notifyAll wait wait wait

Field Detail

serialVersionUID	back to summary
private static final long serialVersionUID Serialization version. Annotations @Serial

SHORT_IDS back to summary

SHORT_IDS	back to summary
public static final Map<String, String> SHORT_IDS A map of zone overrides to enable the short time-zone names to be used. Use of short zone IDs has been deprecated in `java.util.TimeZone`. This map allows the IDs to continue to be used via the `of(String, Map)` factory method. This map contains a mapping of the IDs that is in line with TZDB 2024b and later, where 'EST', 'MST' and 'HST' map to IDs which do not include daylight savings since 1970. This mapping may change in update releases in support of new versions of TZDB. This maps as follows: ACT - Australia/Darwin AET - Australia/Sydney AGT - America/Argentina/Buenos_Aires ART - Africa/Cairo AST - America/Anchorage BET - America/Sao_Paulo BST - Asia/Dhaka CAT - Africa/Harare CNT - America/St_Johns CST - America/Chicago CTT - Asia/Shanghai EAT - Africa/Addis_Ababa ECT - Europe/Paris EST - America/Panama HST - Pacific/Honolulu IET - America/Indiana/Indianapolis IST - Asia/Kolkata JST - Asia/Tokyo MIT - Pacific/Apia MST - America/Phoenix NET - Asia/Yerevan NST - Pacific/Auckland PLT - Asia/Karachi PNT - America/Phoenix PRT - America/Puerto_Rico PST - America/Los_Angeles SST - Pacific/Guadalcanal VST - Asia/Ho_Chi_Minh The map is unmodifiable.

public static final Map<String, String> SHORT_IDS

A map of zone overrides to enable the short time-zone names to be used.

Use of short zone IDs has been deprecated in java.util.TimeZone. This map allows the IDs to continue to be used via the of(String, Map) factory method.

This map contains a mapping of the IDs that is in line with TZDB 2024b and later, where 'EST', 'MST' and 'HST' map to IDs which do not include daylight savings since 1970. This mapping may change in update releases in support of new versions of TZDB.

This maps as follows:

ACT - Australia/Darwin
AET - Australia/Sydney
AGT - America/Argentina/Buenos_Aires
ART - Africa/Cairo
AST - America/Anchorage
BET - America/Sao_Paulo
BST - Asia/Dhaka
CAT - Africa/Harare
CNT - America/St_Johns
CST - America/Chicago
CTT - Asia/Shanghai
EAT - Africa/Addis_Ababa
ECT - Europe/Paris
EST - America/Panama
HST - Pacific/Honolulu
IET - America/Indiana/Indianapolis
IST - Asia/Kolkata
JST - Asia/Tokyo
MIT - Pacific/Apia
MST - America/Phoenix
NET - Asia/Yerevan
NST - Pacific/Auckland
PLT - Asia/Karachi
PNT - America/Phoenix
PRT - America/Puerto_Rico
PST - America/Los_Angeles
SST - Pacific/Guadalcanal
VST - Asia/Ho_Chi_Minh

The map is unmodifiable.

Constructor Detail

ZoneId	back to summary
pack-priv ZoneId() Constructor only accessible within the package.

Method Detail

equals	back to summary
public boolean equals(Object obj) Overrides java.lang.Object.equals. Checks if this time-zone ID is equal to another time-zone ID. The comparison is based on the ID. Parameters obj:Object the object to check, null returns false Returns:boolean true if this is equal to the other time-zone ID Annotations @Override

equals

back to summary

public boolean equals(Object obj)

Overrides java.lang.Object.equals.

Checks if this time-zone ID is equal to another time-zone ID.

The comparison is based on the ID.

Parameters

obj:Object: the object to check, null returns false

Returns:boolean

true if this is equal to the other time-zone ID

Annotations

@Override

from back to summary

from	back to summary
public static ZoneId from(TemporalAccessor temporal) Obtains an instance of `ZoneId` from a temporal object. This obtains a zone based on the specified temporal. A `TemporalAccessor` represents an arbitrary set of date and time information, which this factory converts to an instance of `ZoneId`. A `TemporalAccessor` represents some form of date and time information. This factory converts the arbitrary temporal object to an instance of `ZoneId`. The conversion will try to obtain the zone in a way that favours region-based zones over offset-based zones using `TemporalQueries#zone()`. This method matches the signature of the functional interface `TemporalQuery` allowing it to be used as a query via method reference, `ZoneId::from`. Parameters temporal:TemporalAccessor the temporal object to convert, not null Returns:ZoneId the zone ID, not null Exceptions DateTimeException: if unable to convert to a `ZoneId`

public static ZoneId from(TemporalAccessor temporal)

Obtains an instance of ZoneId from a temporal object.

This obtains a zone based on the specified temporal. A TemporalAccessor represents an arbitrary set of date and time information, which this factory converts to an instance of ZoneId.

A TemporalAccessor represents some form of date and time information. This factory converts the arbitrary temporal object to an instance of ZoneId.

The conversion will try to obtain the zone in a way that favours region-based zones over offset-based zones using TemporalQueries#zone().

This method matches the signature of the functional interface TemporalQuery allowing it to be used as a query via method reference, ZoneId::from.

Parameters

temporal:TemporalAccessor: the temporal object to convert, not null

Returns:ZoneId

the zone ID, not null

Exceptions

DateTimeException:: if unable to convert to a ZoneId

getAvailableZoneIds back to summary

getAvailableZoneIds	back to summary
public static Set<String> getAvailableZoneIds() Gets the set of available zone IDs. 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 `of(String)` to create a `ZoneId`. 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. Returns:Set<String> a modifiable copy of the set of zone IDs, not null

public static Set<String> getAvailableZoneIds()

Gets the set of available zone IDs.

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 of(String) to create a ZoneId.

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.

Returns:Set<String>: a modifiable copy of the set of zone IDs, not null

getDisplayName back to summary

getDisplayName	back to summary
public String getDisplayName(TextStyle style, Locale locale) Gets the textual representation of the zone, such as 'British Time' or '+02:00'. 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. If no textual mapping is found then the `full ID` is returned. Parameters style:TextStyle the length of the text required, not null locale:Locale the locale to use, not null Returns:String the text value of the zone, not null

public String getDisplayName(TextStyle style, Locale locale)

Gets the textual representation of the zone, such as 'British Time' or '+02:00'.

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.

If no textual mapping is found then the full ID is returned.

Parameters

style:TextStyle: the length of the text required, not null
locale:Locale: the locale to use, not null

Returns:String

the text value of the zone, not null

getId back to summary

getId	back to summary
public abstract String getId() Gets the unique time-zone ID. This ID uniquely defines this object. The format of an offset based ID is defined by `ZoneOffset#getId()`. Returns:String the time-zone unique ID, not null

public abstract String getId()

Gets the unique time-zone ID.

This ID uniquely defines this object. The format of an offset based ID is defined by ZoneOffset#getId().

Returns:String: the time-zone unique ID, not null

getOffset	back to summary
pack-priv abstract ZoneOffset getOffset(long epochSecond) Get the effective offset for an instant at the given epochSecond.

getRules back to summary

getRules	back to summary
public abstract ZoneRules getRules() Gets the time-zone rules for this ID allowing calculations to be performed. The rules provide the functionality associated with a time-zone, such as finding the offset for a given instant or local date-time. 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 `ZoneRulesException`. The rules are supplied by `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. `ZoneOffset` will always return a set of rules where the offset never changes. Returns:ZoneRules the rules, not null Exceptions ZoneRulesException: if no rules are available for this ID

public abstract ZoneRules getRules()

Gets the time-zone rules for this ID allowing calculations to be performed.

The rules provide the functionality associated with a time-zone, such as finding the offset for a given instant or local date-time.

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 ZoneRulesException.

The rules are supplied by 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.

ZoneOffset will always return a set of rules where the offset never changes.

Returns:ZoneRules

the rules, not null

Exceptions

ZoneRulesException:: if no rules are available for this ID

hashCode	back to summary
public int hashCode() Overrides java.lang.Object.hashCode. A hash code for this time-zone ID. Returns:int a suitable hash code Annotations @Override

hashCode

back to summary

public int hashCode()

Overrides java.lang.Object.hashCode.

A hash code for this time-zone ID.

Returns:int

a suitable hash code

Annotations

@Override

normalized back to summary

normalized	back to summary
public ZoneId normalized() Normalizes the time-zone ID, returning a `ZoneOffset` where possible. The returns a normalized `ZoneId` that can be used in place of this ID. The result will have `ZoneRules` equivalent to those returned by this object, however the ID returned by `getId()` may be different. The normalization checks if the rules of this `ZoneId` have a fixed offset. If they do, then the `ZoneOffset` equal to that offset is returned. Otherwise `this` is returned. Returns:ZoneId the time-zone unique ID, not null

public ZoneId normalized()

Normalizes the time-zone ID, returning a ZoneOffset where possible.

The returns a normalized ZoneId that can be used in place of this ID. The result will have ZoneRules equivalent to those returned by this object, however the ID returned by getId() may be different.

The normalization checks if the rules of this ZoneId have a fixed offset. If they do, then the ZoneOffset equal to that offset is returned. Otherwise this is returned.

Returns:ZoneId: the time-zone unique ID, not null

of back to summary

of	back to summary
public static ZoneId of(String zoneId, Map<String, String> aliasMap) Obtains an instance of `ZoneId` using its ID using a map of aliases to supplement the standard zone IDs. 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. Parameters zoneId:String the time-zone ID, not null aliasMap:Map<String, String> a map of alias zone IDs (typically abbreviations) to real zone IDs, not null Returns:ZoneId the zone ID, not null Exceptions DateTimeException: if the zone ID has an invalid format ZoneRulesException: if the zone ID is a region ID that cannot be found

public static ZoneId of(String zoneId, Map<String, String> aliasMap)

Obtains an instance of ZoneId using its ID using a map of aliases to supplement the standard zone IDs.

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.

Parameters

zoneId:String: the time-zone ID, not null
aliasMap:Map<String, String>: a map of alias zone IDs (typically abbreviations) to real zone IDs, not null

Returns:ZoneId

the zone ID, not null

Exceptions

DateTimeException:: if the zone ID has an invalid format
ZoneRulesException:: if the zone ID is a region ID that cannot be found

of back to summary

of	back to summary
public static ZoneId of(String zoneId) Obtains an instance of `ZoneId` from an ID ensuring that the ID is valid and available for use. This method parses the ID producing a `ZoneId` or `ZoneOffset`. A `ZoneOffset` is returned if the ID is 'Z', or starts with '+' or '-'. The result will always be a valid ID for which `ZoneRules` can be obtained. Parsing matches the zone ID step by step as follows. If the zone ID equals 'Z', the result is `ZoneOffset.UTC`. If the zone ID consists of a single letter, the zone ID is invalid and `DateTimeException` is thrown. If the zone ID starts with '+' or '-', the ID is parsed as a `ZoneOffset` using `ZoneOffset#of(String)`. If the zone ID equals 'GMT', 'UTC' or 'UT' then the result is a `ZoneId` with the same ID and rules equivalent to `ZoneOffset.UTC`. 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 `ZoneOffset`. The result will be a `ZoneId` with the specified UTC/GMT/UT prefix and the normalized offset ID as per `ZoneOffset#getId()`. The rules of the returned `ZoneId` will be equivalent to the parsed `ZoneOffset`. All other IDs are parsed as region-based zone IDs. Region IDs must match the regular expression `[A-Za-z][A-Za-z0-9~/._+-]+` otherwise a `DateTimeException` is thrown. If the zone ID is not in the configured set of IDs, `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 `java.util.TimeZone`. Parameters zoneId:String the time-zone ID, not null Returns:ZoneId the zone ID, not null Exceptions DateTimeException: if the zone ID has an invalid format ZoneRulesException: if the zone ID is a region ID that cannot be found

public static ZoneId of(String zoneId)

Obtains an instance of ZoneId from an ID ensuring that the ID is valid and available for use.

This method parses the ID producing a ZoneId or ZoneOffset. A ZoneOffset is returned if the ID is 'Z', or starts with '+' or '-'. The result will always be a valid ID for which ZoneRules can be obtained.

Parsing matches the zone ID step by step as follows.

If the zone ID equals 'Z', the result is ZoneOffset.UTC.
If the zone ID consists of a single letter, the zone ID is invalid and DateTimeException is thrown.
If the zone ID starts with '+' or '-', the ID is parsed as a ZoneOffset using ZoneOffset#of(String).
If the zone ID equals 'GMT', 'UTC' or 'UT' then the result is a ZoneId with the same ID and rules equivalent to ZoneOffset.UTC.
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 ZoneOffset. The result will be a ZoneId with the specified UTC/GMT/UT prefix and the normalized offset ID as per ZoneOffset#getId(). The rules of the returned ZoneId will be equivalent to the parsed ZoneOffset.
All other IDs are parsed as region-based zone IDs. Region IDs must match the regular expression [A-Za-z][A-Za-z0-9~/._+-]+ otherwise a DateTimeException is thrown. If the zone ID is not in the configured set of IDs, 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 java.util.TimeZone.

Parameters

zoneId:String: the time-zone ID, not null

Returns:ZoneId

the zone ID, not null

Exceptions

DateTimeException:: if the zone ID has an invalid format
ZoneRulesException:: if the zone ID is a region ID that cannot be found

of back to summary

of	back to summary
pack-priv static ZoneId of(String zoneId, boolean checkAvailable) Parses the ID, taking a flag to indicate whether `ZoneRulesException` should be thrown or not, used in deserialization. Parameters zoneId:String the time-zone ID, not null checkAvailable:boolean whether to check if the zone ID is available Returns:ZoneId the zone ID, not null Exceptions DateTimeException: if the ID format is invalid ZoneRulesException: if checking availability and the ID cannot be found

pack-priv static ZoneId of(String zoneId, boolean checkAvailable)

Parses the ID, taking a flag to indicate whether ZoneRulesException should be thrown or not, used in deserialization.

Parameters

zoneId:String: the time-zone ID, not null
checkAvailable:boolean: whether to check if the zone ID is available

Returns:ZoneId

the zone ID, not null

Exceptions

DateTimeException:: if the ID format is invalid
ZoneRulesException:: if checking availability and the ID cannot be found

ofOffset back to summary

ofOffset	back to summary
public static ZoneId ofOffset(String prefix, ZoneOffset offset) Obtains an instance of `ZoneId` wrapping an offset. If the prefix is "GMT", "UTC", or "UT" a `ZoneId` with the prefix and the non-zero offset is returned. If the prefix is empty `""` the `ZoneOffset` is returned. Parameters prefix:String the time-zone ID, not null offset:ZoneOffset the offset, not null Returns:ZoneId the zone ID, not null Exceptions IllegalArgumentException: if the prefix is not one of "GMT", "UTC", or "UT", or ""

public static ZoneId ofOffset(String prefix, ZoneOffset offset)

Obtains an instance of ZoneId wrapping an offset.

If the prefix is "GMT", "UTC", or "UT" a ZoneId with the prefix and the non-zero offset is returned. If the prefix is empty "" the ZoneOffset is returned.

Parameters

prefix:String: the time-zone ID, not null
offset:ZoneOffset: the offset, not null

Returns:ZoneId

the zone ID, not null

Exceptions

IllegalArgumentException:: if the prefix is not one of "GMT", "UTC", or "UT", or ""

ofWithPrefix	back to summary
private static ZoneId ofWithPrefix(String zoneId, int prefixLength, boolean checkAvailable) Parse once a prefix is established. Parameters zoneId:String the time-zone ID, not null prefixLength:int the length of the prefix, 2 or 3 Returns:ZoneId the zone ID, not null Exceptions DateTimeException: if the zone ID has an invalid format

ofWithPrefix

back to summary

private static ZoneId ofWithPrefix(String zoneId, int prefixLength, boolean checkAvailable)

Parse once a prefix is established.

Parameters

zoneId:String: the time-zone ID, not null
prefixLength:int: the length of the prefix, 2 or 3

Returns:ZoneId

the zone ID, not null

Exceptions

DateTimeException:: if the zone ID has an invalid format

readObject	back to summary
private void readObject(ObjectInputStream s) throws InvalidObjectException Defend against malicious streams. Parameters s:ObjectInputStream the stream to read Annotations @Serial Exceptions InvalidObjectException: always

readObject

back to summary

private void readObject(ObjectInputStream s) throws InvalidObjectException

Defend against malicious streams.

Parameters

s:ObjectInputStream: the stream to read

Annotations

@Serial

Exceptions

InvalidObjectException:: always

systemDefault back to summary

systemDefault	back to summary
public static ZoneId systemDefault() Gets the system default time-zone. This queries `TimeZone#getDefault()` to find the default time-zone and converts it to a `ZoneId`. If the system default time-zone is changed, then the result of this method will also change. Returns:ZoneId the zone ID, not null Exceptions DateTimeException: if the converted zone ID has an invalid format ZoneRulesException: if the converted zone region ID cannot be found

public static ZoneId systemDefault()

Gets the system default time-zone.

This queries TimeZone#getDefault() to find the default time-zone and converts it to a ZoneId. If the system default time-zone is changed, then the result of this method will also change.

Returns:ZoneId

the zone ID, not null

Exceptions

DateTimeException:: if the converted zone ID has an invalid format
ZoneRulesException:: if the converted zone region ID cannot be found

toString back to summary

toString	back to summary
public String toString() Overrides java.lang.Object.toString. Outputs this zone as a `String`, using the ID. Returns:String a string representation of this time-zone ID, not null Annotations @Override

public String toString()

Overrides java.lang.Object.toString.

Outputs this zone as a String, using the ID.

Returns:String

a string representation of this time-zone ID, not null

Annotations

@Override

toTemporal back to summary

toTemporal	back to summary
private TemporalAccessor toTemporal() Converts this zone to a `TemporalAccessor`. A `ZoneId` can be fully represented as a `TemporalAccessor`. However, the interface is not implemented by this class as most of the methods on the interface have no meaning to `ZoneId`. The returned temporal has no supported fields, with the query method supporting the return of the zone using `TemporalQueries#zoneId()`. Returns:TemporalAccessor a temporal equivalent to this zone, not null

private TemporalAccessor toTemporal()

Converts this zone to a TemporalAccessor.

A ZoneId can be fully represented as a TemporalAccessor. However, the interface is not implemented by this class as most of the methods on the interface have no meaning to ZoneId.

The returned temporal has no supported fields, with the query method supporting the return of the zone using TemporalQueries#zoneId().

Returns:TemporalAccessor: a temporal equivalent to this zone, not null

write	back to summary
pack-priv abstract void write(DataOutput out) throws IOException

writeReplace back to summary

writeReplace	back to summary
private Object writeReplace() Writes the object using a dedicated serialized form. Returns:Object the instance of `Ser`, not null Annotations @Serial Serial data out.writeByte(7); // identifies a ZoneId (not ZoneOffset) out.writeUTF(getId()); When read back in, the `ZoneId` will be created as though using `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.

private Object writeReplace()

Writes the object using a dedicated serialized form.

Returns:Object

the instance of Ser, not null

Annotations

@Serial

Serial data

 out.writeByte(7);  // identifies a ZoneId (not ZoneOffset)
 out.writeUTF(getId());

When read back in, the ZoneId will be created as though using 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.

public abstract sealed Class ZoneId

Time-zone IDs

Serialization

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail