Top Description Fields Constructors Methods
java.util

public abstract Class TimeZone

extends Object
implements Serializable, Cloneable
Class Inheritance
All Implemented Interfaces
java.lang.Cloneable, java.io.Serializable
Known Direct Subclasses
sun.util.calendar.ZoneInfo, java.util.SimpleTimeZone
Imports
java.io.Serializable, java.time.ZoneId, .ZoneOffset, jdk.internal.util.StaticProperty, sun.security.action.GetPropertyAction, sun.util.calendar.ZoneInfo, .ZoneInfoFile, sun.util.locale.provider.TimeZoneNameUtility
TimeZone represents a time zone offset, and also figures out daylight savings.

Typically, you get a TimeZone using getDefault which creates a TimeZone based on the time zone where the program is running. For example, for a program running in Japan, getDefault creates a TimeZone object based on Japanese Standard Time.

You can also get a TimeZone using getTimeZone along with a time zone ID. For instance, the time zone ID for the U.S. Pacific Time zone is "America/Los_Angeles". So, you can get a U.S. Pacific Time TimeZone object with:

TimeZone tz = TimeZone.getTimeZone("America/Los_Angeles"); 
TimeZone tz = TimeZone.getTimeZone("America/Los_Angeles");
You can use the getAvailableIDs method to iterate through all the supported time zone IDs. You can then choose a supported ID to get a TimeZone. If the time zone you want is not represented by one of the supported IDs, then a custom time zone ID can be specified to produce a TimeZone. The syntax of a custom time zone ID is: 
CustomID:
        GMT Sign Hours : Minutes : Seconds
        GMT Sign Hours : Minutes
        GMT Sign Hours Minutes
        GMT Sign Hours
Sign: one of
        + -
Hours:
        Digit
        Digit Digit
Minutes:
        Digit Digit
Seconds:
        Digit Digit
Digit: one of
        0 1 2 3 4 5 6 7 8 9
Hours must be between 0 to 23 and Minutes/Seconds must be between 00 to 59. For example, "GMT+10" and "GMT+0010" mean ten hours and ten minutes ahead of GMT, respectively.

The format is locale independent and digits must be taken from the Basic Latin block of the Unicode standard. No daylight saving time transition schedule can be specified with a custom time zone ID. If the specified string doesn't match the syntax, "GMT" is used.

When creating a TimeZone, the specified custom time zone ID is normalized in the following syntax: 

NormalizedCustomID:
        GMT Sign TwoDigitHours : Minutes [ColonSeconds]
Sign: one of
        + -
TwoDigitHours:
        Digit Digit
Minutes:
        Digit Digit
ColonSeconds:
        : Digit Digit
Digit: one of
        0 1 2 3 4 5 6 7 8 9
For example, TimeZone.getTimeZone("GMT-8").getID() returns "GMT-08:00". ColonSeconds part only appears if the seconds value is non-zero.

Three-letter time zone IDs

For compatibility with JDK 1.1.x, some other three-letter time zone IDs (such as "PST", "CTT", "AST") are also supported. However, their use is deprecated because the same abbreviation is often used for multiple time zones (for example, "CST" could be U.S. "Central Standard Time" and "China Standard Time"), and the Java platform can then only recognize one of them. The full list of deprecated three-letter time zone IDs and their mappings can be viewed at java.time.ZoneId#SHORT_IDS.
Author
Mark Davis, David Goldsmith, Chen-Lieh Huang, Alan Liu
Since
1.1
See Also
Calendar, GregorianCalendar, SimpleTimeZone

Field Summary

Modifier and TypeField and Description
private static volatile TimeZone
defaultTimeZone

pack-priv static final String
GMT_ID

private static final int
GMT_ID_LENGTH

private String
ID

The string identifier of this TimeZone.

public static final int
LONG

A style specifier for getDisplayName() indicating a long name, such as "Pacific Standard Time."

pack-priv static final TimeZone
NO_TIMEZONE

The null constant as a TimeZone.

private static final int
ONE_DAY

private static final int
ONE_HOUR

private static final int
ONE_MINUTE

pack-priv static final long
serialVersionUID

public static final int
SHORT

A style specifier for getDisplayName() indicating a short name, such as "PST."

private transient ZoneId
zoneId

Cached ZoneId for this TimeZone

Constructor Summary

AccessConstructor and Description
public
TimeZone()

Sole constructor.

Method Summary

Modifier and TypeMethod and Description
public Object

Returns:

a clone of this TimeZone
clone()

Overrides java.lang.Object.clone.

Creates a copy of this TimeZone.

public static synchronized String[]

Returns:

an array of IDs, where the time zone for that ID has the specified GMT offset. For example, "America/Phoenix" and "America/Denver" both have GMT-07:00, but differ in daylight saving behavior.
getAvailableIDs(int
the given time zone GMT offset in milliseconds.
rawOffset)

Gets the available IDs according to the given time zone offset in milliseconds.

public static synchronized String[]

Returns:

an array of IDs.
getAvailableIDs()

Gets all the available IDs supported.

public static TimeZone

Returns:

the default TimeZone
getDefault()

Gets the default TimeZone of the Java virtual machine.

pack-priv static TimeZone
getDefaultRef()

Returns the reference to the default TimeZone object.

public final String

Returns:

the human-readable name of this time zone in the default locale.
getDisplayName()

Returns a long standard time name of this TimeZone suitable for presentation to the user in the default locale.

public final String

Returns:

the human-readable name of this time zone in the given locale.
getDisplayName(Locale
the locale in which to supply the display name.
locale)

Returns a long standard time name of this TimeZone suitable for presentation to the user in the specified locale.

public final String

Returns:

the human-readable name of this time zone in the default locale.
getDisplayName(boolean
true specifying a Daylight Saving Time name, or false specifying a Standard Time name
daylight, int
either LONG or SHORT
style)

Returns a name in the specified style of this TimeZone suitable for presentation to the user in the default locale.

public String

Returns:

the human-readable name of this time zone in the given locale.
getDisplayName(boolean
true specifying a Daylight Saving Time name, or false specifying a Standard Time name
daylight, int
either LONG or SHORT
style, Locale
the locale in which to supply the display name.
locale)

Returns a name in the specified style of this TimeZone suitable for presentation to the user in the specified locale.

private static String[]
getDisplayNames(String id, Locale locale)

public int

Returns:

the amount of saving time in milliseconds
getDSTSavings()

Returns the amount of time to be added to local standard time to get local wall clock time.

public String

Returns:

the ID of this time zone.
getID()

Gets the ID of this time zone.

public abstract int

Returns:

the offset in milliseconds to add to GMT to get local time.
getOffset(int
the era of the given date.
era, int
the year in the given date.
year, int
the month in the given date. Month is 0-based. e.g., 0 for January.
month, int
the day-in-month of the given date.
day, int
the day-of-week of the given date.
dayOfWeek, int
the milliseconds in day in standard local time.
milliseconds)

Gets the time zone offset, for current date, modified in case of daylight savings.

public int

Returns:

the amount of time in milliseconds to add to UTC to get local time.
getOffset(long
the date represented in milliseconds since January 1, 1970 00:00:00 GMT
date)

Returns the offset of this time zone from UTC at the specified date.

pack-priv int

Returns:

the total amount of the raw GMT offset and daylight saving at the specified date.
getOffsets(long
the milliseconds (since January 1, 1970, 00:00:00.000 GMT) at which the time zone offset and daylight saving amount are found
date, int[]
an array of int where the raw GMT offset (offset[0]) and daylight saving amount (offset[1]) are stored, or null if those values are not needed. The method assumes that the length of the given array is two or larger.
offsets)

Gets the raw GMT offset and the amount of daylight saving of this time zone at the given time.

public abstract int

Returns:

the amount of raw offset time in milliseconds to add to UTC.
getRawOffset()

Returns the amount of time in milliseconds to add to UTC to get standard time in this time zone.

private static native String
getSystemGMTOffsetID()

Gets the custom time zone ID based on the GMT offset of the platform.

private static native String
getSystemTimeZoneID(String javaHome)

Gets the platform defined TimeZone ID.

public static synchronized TimeZone

Returns:

the specified TimeZone, or the GMT zone if the given ID cannot be understood.
getTimeZone(String
the ID for a TimeZone, either an abbreviation such as "PST", a full name such as "America/Los_Angeles", or a custom ID such as "GMT-8:00". Note that the support of abbreviations is for JDK 1.1.x compatibility only and full names should be used.
ID)

Gets the TimeZone for the given ID.

public static TimeZone

Returns:

the specified TimeZone, or the GMT zone if the given ID cannot be understood.
getTimeZone(ZoneId
a ZoneId from which the time zone ID is obtained
zoneId)

Gets the TimeZone for the given zoneId.

private static TimeZone
getTimeZone(String ID, boolean fallback)

public boolean

Returns:

true if the other zone is not null and is the same as this one, with the possible exception of the ID
hasSameRules(TimeZone
the TimeZone object to be compared with
other)

Returns true if this zone has the same rule and offset as another zone.

public abstract boolean

Returns:

true if the given date is in Daylight Saving Time, false, otherwise.
inDaylightTime(Date
the given Date.
date)

Queries if the given date is in Daylight Saving Time in this time zone.

public boolean

Returns:

true if this TimeZone is currently in Daylight Saving Time, or if a transition from Standard Time to Daylight Saving Time occurs at any future time; false otherwise.
observesDaylightTime()

Returns true if this TimeZone is currently in Daylight Saving Time, or if a transition from Standard Time to Daylight Saving Time occurs at any future time.

private static final TimeZone

Returns:

a newly created TimeZone with the given offset and no daylight saving time, or null if the id cannot be parsed.
parseCustomTimeZone(String
a string of the custom ID form.
id)

Parses a custom time zone identifier and returns a corresponding zone.

public static void
setDefault(TimeZone
the new default TimeZone, or null
zone)

Sets the TimeZone that is returned by the getDefault method.

private static synchronized TimeZone
setDefaultZone()

public void
setID(String
the new time zone ID.
ID)

Sets the time zone ID. This does not change any other data in the time zone object.

public abstract void
setRawOffset(int
the given base time zone offset to GMT.
offsetMillis)

Sets the base time zone offset to GMT.

public ZoneId

Returns:

a ZoneId representing the same time zone as this TimeZone
toZoneId()

Converts this TimeZone object to a ZoneId.

private ZoneId
toZoneId0()

public abstract boolean

Returns:

true if this TimeZone uses Daylight Saving Time, false, otherwise.
useDaylightTime()

Queries if this TimeZone uses Daylight Saving Time.

Inherited from java.lang.Object:
equalsfinalizegetClasshashCodenotifynotifyAlltoStringwaitwaitwait

Field Detail

defaultTimeZoneback to summary
private static volatile TimeZone defaultTimeZone
GMT_IDback to summary
pack-priv static final String GMT_ID
GMT_ID_LENGTHback to summary
private static final int GMT_ID_LENGTH
IDback to summary
private String ID

The string identifier of this TimeZone. This is a programmatic identifier used internally to look up TimeZone objects from the system table and also to map them to their localized display names. ID values are unique in the system table but may not be for dynamically created zones.

LONGback to summary
public static final int LONG

A style specifier for getDisplayName() indicating a long name, such as "Pacific Standard Time."

Since
1.2
See Also
SHORT
NO_TIMEZONEback to summary
pack-priv static final TimeZone NO_TIMEZONE

The null constant as a TimeZone.

ONE_DAYback to summary
private static final int ONE_DAY
ONE_HOURback to summary
private static final int ONE_HOUR
ONE_MINUTEback to summary
private static final int ONE_MINUTE
serialVersionUIDback to summary
pack-priv static final long serialVersionUID
Annotations
@Serial
SHORTback to summary
public static final int SHORT

A style specifier for getDisplayName() indicating a short name, such as "PST."

Since
1.2
See Also
LONG
zoneIdback to summary
private transient ZoneId zoneId

Cached ZoneId for this TimeZone

Constructor Detail

TimeZoneback to summary
public TimeZone()

Sole constructor. (For invocation by subclass constructors, typically implicit.)

Method Detail

cloneback to summary
public Object clone()

Overrides java.lang.Object.clone.

Creates a copy of this TimeZone.

Returns:Object

a clone of this TimeZone

getAvailableIDsback to summary
public static synchronized String[] getAvailableIDs(int rawOffset)

Gets the available IDs according to the given time zone offset in milliseconds.

Parameters
rawOffset:int

the given time zone GMT offset in milliseconds.

Returns:String[]

an array of IDs, where the time zone for that ID has the specified GMT offset. For example, "America/Phoenix" and "America/Denver" both have GMT-07:00, but differ in daylight saving behavior.

See Also
getRawOffset()
getAvailableIDsback to summary
public static synchronized String[] getAvailableIDs()

Gets all the available IDs supported.

Returns:String[]

an array of IDs.

getDefaultback to summary
public static TimeZone getDefault()

Gets the default TimeZone of the Java virtual machine. If the cached default TimeZone is available, its clone is returned. Otherwise, the method takes the following steps to determine the default time zone.

  • Use the user.timezone property value as the default time zone ID if it's available.
  • Detect the platform time zone ID. The source of the platform time zone and ID mapping may vary with implementation.
  • Use GMT as the last resort if the given or detected time zone ID is unknown.

The default TimeZone created from the ID is cached, and its clone is returned. The user.timezone property value is set to the ID upon return.

Returns:TimeZone

the default TimeZone

See Also
setDefault(TimeZone)
getDefaultRefback to summary
pack-priv static TimeZone getDefaultRef()

Returns the reference to the default TimeZone object. This method doesn't create a clone.

getDisplayNameback to summary
public final String getDisplayName()

Returns a long standard time name of this TimeZone suitable for presentation to the user in the default locale.

This method is equivalent to:

getDisplayName(false, LONG, Locale.getDefault(Locale.Category.DISPLAY)); 
getDisplayName(false, LONG,
               Locale.getDefault(Locale.Category.DISPLAY));
Returns:String

the human-readable name of this time zone in the default locale.

Since
1.2
See Also
getDisplayName(boolean, int, Locale), Locale#getDefault(Locale.Category), Locale.Category
getDisplayNameback to summary
public final String getDisplayName(Locale locale)

Returns a long standard time name of this TimeZone suitable for presentation to the user in the specified locale.

This method is equivalent to:

getDisplayName(false, LONG, locale); 
getDisplayName(false, LONG, locale);
Parameters
locale:Locale

the locale in which to supply the display name.

Returns:String

the human-readable name of this time zone in the given locale.

Exceptions
NullPointerException:
if locale is null.
Since
1.2
See Also
getDisplayName(boolean, int, Locale)
getDisplayNameback to summary
public final String getDisplayName(boolean daylight, int style)

Returns a name in the specified style of this TimeZone suitable for presentation to the user in the default locale. If the specified daylight is true, a Daylight Saving Time name is returned (even if this TimeZone doesn't observe Daylight Saving Time). Otherwise, a Standard Time name is returned.

This method is equivalent to:

getDisplayName(daylight, style, Locale.getDefault(Locale.Category.DISPLAY)); 
getDisplayName(daylight, style,
               Locale.getDefault(Locale.Category.DISPLAY));
Parameters
daylight:boolean

true specifying a Daylight Saving Time name, or false specifying a Standard Time name

style:int

either LONG or SHORT

Returns:String

the human-readable name of this time zone in the default locale.

Exceptions
IllegalArgumentException:
if style is invalid.
Since
1.2
See Also
getDisplayName(boolean, int, Locale), Locale#getDefault(Locale.Category), Locale.Category, java.text.DateFormatSymbols#getZoneStrings()
getDisplayNameback to summary
public String getDisplayName(boolean daylight, int style, Locale locale)

Returns a name in the specified style of this TimeZone suitable for presentation to the user in the specified locale. If the specified daylight is true, a Daylight Saving Time name is returned (even if this TimeZone doesn't observe Daylight Saving Time). Otherwise, a Standard Time name is returned.

When looking up a time zone name, the default Locale search path of ResourceBundle derived from the specified locale is used. (No fallback Locale search is performed.) If a time zone name in any Locale of the search path, including Locale#ROOT, is found, the name is returned. Otherwise, a string in the normalized custom ID format is returned.

Implementation Specification

The default implementation throws an IllegalArgumentException if style is invalid or a NullPointerException if ID is null.

Parameters
daylight:boolean

true specifying a Daylight Saving Time name, or false specifying a Standard Time name

style:int

either LONG or SHORT

locale:Locale

the locale in which to supply the display name.

Returns:String

the human-readable name of this time zone in the given locale.

Exceptions
IllegalArgumentException:
This method may throw an IllegalArgumentException if style is invalid.
NullPointerException:
This method may throw a NullPointerException if ID is null
Since
1.2
See Also
java.text.DateFormatSymbols#getZoneStrings()
getDisplayNamesback to summary
private static String[] getDisplayNames(String id, Locale locale)
getDSTSavingsback to summary
public int getDSTSavings()

Returns the amount of time to be added to local standard time to get local wall clock time.

The default implementation returns 3600000 milliseconds (i.e., one hour) if a call to useDaylightTime() returns true. Otherwise, 0 (zero) is returned.

If an underlying TimeZone implementation subclass supports historical and future Daylight Saving Time schedule changes, this method returns the amount of saving time of the last known Daylight Saving Time rule that can be a future prediction.

If the amount of saving time at any given time stamp is required, construct a Calendar with this TimeZone and the time stamp, and call Calendar.get(Calendar#DST_OFFSET).

Returns:int

the amount of saving time in milliseconds

Since
1.4
See Also
inDaylightTime(Date), getOffset(long), getOffset(int, int, int, int, int, int), Calendar#ZONE_OFFSET
getIDback to summary
public String getID()

Gets the ID of this time zone.

Returns:String

the ID of this time zone.

getOffsetback to summary
public abstract int getOffset(int era, int year, int month, int day, int dayOfWeek, int milliseconds)

Gets the time zone offset, for current date, modified in case of daylight savings. This is the offset to add to UTC to get local time.

This method returns a historically correct offset if an underlying TimeZone implementation subclass supports historical Daylight Saving Time schedule and GMT offset changes.

Parameters
era:int

the era of the given date.

year:int

the year in the given date.

month:int

the month in the given date. Month is 0-based. e.g., 0 for January.

day:int

the day-in-month of the given date.

dayOfWeek:int

the day-of-week of the given date.

milliseconds:int

the milliseconds in day in standard local time.

Returns:int

the offset in milliseconds to add to GMT to get local time.

See Also
Calendar#ZONE_OFFSET, Calendar#DST_OFFSET
getOffsetback to summary
public int getOffset(long date)

Returns the offset of this time zone from UTC at the specified date. If Daylight Saving Time is in effect at the specified date, the offset value is adjusted with the amount of daylight saving.

This method returns a historically correct offset value if an underlying TimeZone implementation subclass supports historical Daylight Saving Time schedule and GMT offset changes.

Parameters
date:long

the date represented in milliseconds since January 1, 1970 00:00:00 GMT

Returns:int

the amount of time in milliseconds to add to UTC to get local time.

Since
1.4
See Also
Calendar#ZONE_OFFSET, Calendar#DST_OFFSET
getOffsetsback to summary
pack-priv int getOffsets(long date, int[] offsets)

Gets the raw GMT offset and the amount of daylight saving of this time zone at the given time.

Parameters
date:long

the milliseconds (since January 1, 1970, 00:00:00.000 GMT) at which the time zone offset and daylight saving amount are found

offsets:int[]

an array of int where the raw GMT offset (offset[0]) and daylight saving amount (offset[1]) are stored, or null if those values are not needed. The method assumes that the length of the given array is two or larger.

Returns:int

the total amount of the raw GMT offset and daylight saving at the specified date.

See Also
Calendar#ZONE_OFFSET, Calendar#DST_OFFSET
getRawOffsetback to summary
public abstract int getRawOffset()

Returns the amount of time in milliseconds to add to UTC to get standard time in this time zone. Because this value is not affected by daylight saving time, it is called raw offset.

If an underlying TimeZone implementation subclass supports historical GMT offset changes, the method returns the raw offset value of the current date. In Honolulu, for example, its raw offset changed from GMT-10:30 to GMT-10:00 in 1947, and this method always returns -36000000 milliseconds (i.e., -10 hours).

Returns:int

the amount of raw offset time in milliseconds to add to UTC.

See Also
Calendar#ZONE_OFFSET
getSystemGMTOffsetIDback to summary
private static native String getSystemGMTOffsetID()

Gets the custom time zone ID based on the GMT offset of the platform. (e.g., "GMT+08:00")

getSystemTimeZoneIDback to summary
private static native String getSystemTimeZoneID(String javaHome)

Gets the platform defined TimeZone ID.

getTimeZoneback to summary
public static synchronized TimeZone getTimeZone(String ID)

Gets the TimeZone for the given ID.

Parameters
ID:String

the ID for a TimeZone, either an abbreviation such as "PST", a full name such as "America/Los_Angeles", or a custom ID such as "GMT-8:00". Note that the support of abbreviations is for JDK 1.1.x compatibility only and full names should be used.

Returns:TimeZone

the specified TimeZone, or the GMT zone if the given ID cannot be understood.

Exceptions
NullPointerException:
if ID is null
getTimeZoneback to summary
public static TimeZone getTimeZone(ZoneId zoneId)

Gets the TimeZone for the given zoneId.

Parameters
zoneId:ZoneId

a ZoneId from which the time zone ID is obtained

Returns:TimeZone

the specified TimeZone, or the GMT zone if the given ID cannot be understood.

Exceptions
NullPointerException:
if zoneId is null
Since
1.8
getTimeZoneback to summary
private static TimeZone getTimeZone(String ID, boolean fallback)
hasSameRulesback to summary
public boolean hasSameRules(TimeZone other)

Returns true if this zone has the same rule and offset as another zone. That is, if this zone differs only in ID, if at all. Returns false if the other zone is null.

Parameters
other:TimeZone

the TimeZone object to be compared with

Returns:boolean

true if the other zone is not null and is the same as this one, with the possible exception of the ID

Since
1.2
inDaylightTimeback to summary
public abstract boolean inDaylightTime(Date date)

Queries if the given date is in Daylight Saving Time in this time zone.

Parameters
date:Date

the given Date.

Returns:boolean

true if the given date is in Daylight Saving Time, false, otherwise.

Exceptions
NullPointerException:
This method may throw a NullPointerException if date is null
observesDaylightTimeback to summary
public boolean observesDaylightTime()

Returns true if this TimeZone is currently in Daylight Saving Time, or if a transition from Standard Time to Daylight Saving Time occurs at any future time.

The default implementation returns true if useDaylightTime() or inDaylightTime(new Date()) returns true.

Returns:boolean

true if this TimeZone is currently in Daylight Saving Time, or if a transition from Standard Time to Daylight Saving Time occurs at any future time; false otherwise.

Since
1.7
See Also
useDaylightTime(), inDaylightTime(Date), Calendar#DST_OFFSET
parseCustomTimeZoneback to summary
private static final TimeZone parseCustomTimeZone(String id)

Parses a custom time zone identifier and returns a corresponding zone. This method doesn't support the RFC 822 time zone format. (e.g., +hhmm)

Parameters
id:String

a string of the custom ID form.

Returns:TimeZone

a newly created TimeZone with the given offset and no daylight saving time, or null if the id cannot be parsed.

setDefaultback to summary
public static void setDefault(TimeZone zone)

Sets the TimeZone that is returned by the getDefault method. zone is cached. If zone is null, the cached default TimeZone is cleared. This method doesn't change the value of the user.timezone property.

Parameters
zone:TimeZone

the new default TimeZone, or null

Exceptions
SecurityException:
if the security manager's checkPermission denies PropertyPermission("user.timezone", "write")
See Also
getDefault, PropertyPermission
setDefaultZoneback to summary
private static synchronized TimeZone setDefaultZone()
setIDback to summary
public void setID(String ID)

Sets the time zone ID. This does not change any other data in the time zone object.

Implementation Specification

The default implementation throws a NullPointerException if ID is null

Parameters
ID:String

the new time zone ID.

Exceptions
NullPointerException:
This method may throw a NullPointerException if ID is null
setRawOffsetback to summary
public abstract void setRawOffset(int offsetMillis)

Sets the base time zone offset to GMT. This is the offset to add to UTC to get local time.

If an underlying TimeZone implementation subclass supports historical GMT offset changes, the specified GMT offset is set as the latest GMT offset and the difference from the known latest GMT offset value is used to adjust all historical GMT offset values.

Parameters
offsetMillis:int

the given base time zone offset to GMT.

toZoneIdback to summary
public ZoneId toZoneId()

Converts this TimeZone object to a ZoneId.

Returns:ZoneId

a ZoneId representing the same time zone as this TimeZone

Since
1.8
toZoneId0back to summary
private ZoneId toZoneId0()
useDaylightTimeback to summary
public abstract boolean useDaylightTime()

Queries if this TimeZone uses Daylight Saving Time.

If an underlying TimeZone implementation subclass supports historical and future Daylight Saving Time schedule changes, this method refers to the last known Daylight Saving Time rule that can be a future prediction and may not be the same as the current rule. Consider calling observesDaylightTime() if the current rule should also be taken into account.

Returns:boolean

true if this TimeZone uses Daylight Saving Time, false, otherwise.

See Also
inDaylightTime(Date), Calendar#DST_OFFSET