Serializable
, Cloneable
, Comparable<Date>
public class Date extends Object implements Serializable, Cloneable, Comparable<Date>
Date
represents a specific instant in time, with millisecond precision. Prior to JDK 1.1, the class Date
had two additional functions. It allowed the interpretation of dates as year, month, day, hour, minute, and second values. It also allowed the formatting and parsing of date strings. Unfortunately, the API for these functions was not amenable to internationalization. As of JDK 1.1, the Calendar
class should be used to convert between dates and time fields and the DateFormat
class should be used to format and parse date strings. The corresponding methods in Date
are deprecated.
Although the Date
class is intended to reflect coordinated universal time (UTC), it may not do so exactly, depending on the host environment of the Java Virtual Machine. Nearly all modern operating systems assume that 1 day = 24 × 60 × 60 = 86400 seconds in all cases. In UTC, however, about once every year or two there is an extra second, called a "leap second." The leap second is always added as the last second of the day, and always on December 31 or June 30. For example, the last minute of the year 1995 was 61 seconds long, thanks to an added leap second. Most computer clocks are not accurate enough to be able to reflect the leap-second distinction.
Some computer standards are defined in terms of Greenwich mean time (GMT), which is equivalent to universal time (UT). GMT is the "civil" name for the standard; UT is the "scientific" name for the same standard. The distinction between UTC and UT is that UTC is based on an atomic clock and UT is based on astronomical observations, which for all practical purposes is an invisibly fine hair to split. Because the earth's rotation is not uniform (it slows down and speeds up in complicated ways), UT does not always flow uniformly. Leap seconds are introduced as needed into UTC so as to keep UTC within 0.9 seconds of UT1, which is a version of UT with certain corrections applied. There are other time and date systems as well; for example, the time scale used by the satellite-based global positioning system (GPS) is synchronized to UTC but is not adjusted for leap seconds. An interesting source of further information is the United States Naval Observatory (USNO):
https://www.usno.navy.mil/USNO
and the material regarding "Systems of Time" at:
https://www.usno.navy.mil/USNO/time/master-clock/systems-of-time
which has descriptions of various different time systems including UT, UT1, and UTC.
In all methods of class Date
that accept or return year, month, date, hours, minutes, and seconds values, the following representations are used:
- 1900
. In all cases, arguments given to methods for these purposes need not fall within the indicated ranges; for example, a date may be specified as January 32 and is interpreted as meaning February 1.
Constructor | Description |
---|---|
Date() |
Allocates a Date object and initializes it so that it represents the time at which it was allocated, measured to the nearest millisecond. |
Date |
Deprecated. |
Date |
Deprecated. As of JDK version 1.1, replaced by Calendar.set(year + 1900, month, date, hrs, min) or GregorianCalendar(year + 1900, month, date, hrs, min) . |
Date |
Deprecated. As of JDK version 1.1, replaced by Calendar.set(year + 1900, month, date, hrs, min, sec) or GregorianCalendar(year + 1900, month, date, hrs, min, sec) . |
Date |
Allocates a Date object and initializes it to represent the specified number of milliseconds since the standard base time known as "the epoch", namely January 1, 1970, 00:00:00 GMT. |
Date |
Deprecated. As of JDK version 1.1, replaced by DateFormat.parse(String s) . |
Modifier and Type | Method | Description |
---|---|---|
boolean |
after |
Tests if this date is after the specified date. |
boolean |
before |
Tests if this date is before the specified date. |
Object |
clone() |
Return a copy of this object. |
int |
compareTo |
Compares two Dates for ordering. |
boolean |
equals |
Compares two dates for equality. |
static Date |
from |
Obtains an instance of Date from an Instant object. |
int |
getDate() |
Deprecated. As of JDK version 1.1, replaced by Calendar.get(Calendar.DAY_OF_MONTH) . |
int |
getDay() |
Deprecated. As of JDK version 1.1, replaced by Calendar.get(Calendar.DAY_OF_WEEK) . |
int |
getHours() |
Deprecated. As of JDK version 1.1, replaced by Calendar.get(Calendar.HOUR_OF_DAY) . |
int |
getMinutes() |
Deprecated. As of JDK version 1.1, replaced by Calendar.get(Calendar.MINUTE) . |
int |
getMonth() |
Deprecated. As of JDK version 1.1, replaced by Calendar.get(Calendar.MONTH) . |
int |
getSeconds() |
Deprecated. As of JDK version 1.1, replaced by Calendar.get(Calendar.SECOND) . |
long |
getTime() |
Returns the number of milliseconds since January 1, 1970, 00:00:00 GMT represented by this Date object. |
int |
getTimezoneOffset() |
Deprecated. As of JDK version 1.1, replaced by -(Calendar.get(Calendar.ZONE_OFFSET) +
Calendar.get(Calendar.DST_OFFSET)) / (60 * 1000) . |
int |
getYear() |
Deprecated. As of JDK version 1.1, replaced by Calendar.get(Calendar.YEAR) - 1900 . |
int |
hashCode() |
Returns a hash code value for this object. |
static long |
parse |
Deprecated. As of JDK version 1.1, replaced by DateFormat.parse(String s) . |
void |
setDate |
Deprecated. As of JDK version 1.1, replaced by Calendar.set(Calendar.DAY_OF_MONTH, int date) . |
void |
setHours |
Deprecated. As of JDK version 1.1, replaced by Calendar.set(Calendar.HOUR_OF_DAY, int hours) . |
void |
setMinutes |
Deprecated. As of JDK version 1.1, replaced by Calendar.set(Calendar.MINUTE, int minutes) . |
void |
setMonth |
Deprecated. As of JDK version 1.1, replaced by Calendar.set(Calendar.MONTH, int month) . |
void |
setSeconds |
Deprecated. As of JDK version 1.1, replaced by Calendar.set(Calendar.SECOND, int seconds) . |
void |
setTime |
Sets this Date object to represent a point in time that is time milliseconds after January 1, 1970 00:00:00 GMT. |
void |
setYear |
Deprecated. As of JDK version 1.1, replaced by Calendar.set(Calendar.YEAR, year + 1900) . |
String |
toGMTString() |
Deprecated. As of JDK version 1.1, replaced by DateFormat.format(Date date) , using a GMT TimeZone . |
Instant |
toInstant() |
Converts this Date object to an Instant . |
String |
toLocaleString() |
Deprecated. As of JDK version 1.1, replaced by DateFormat.format(Date date) . |
String |
toString() |
Converts this Date object to a String of the form: |
static long |
UTC |
Deprecated. As of JDK version 1.1, replaced by Calendar.set(year + 1900, month, date, hrs, min, sec) or GregorianCalendar(year + 1900, month, date, hrs, min, sec) , using a UTC TimeZone , followed by Calendar.getTime().getTime() . |
public Date()
Date
object and initializes it so that it represents the time at which it was allocated, measured to the nearest millisecond.public Date(long date)
Date
object and initializes it to represent the specified number of milliseconds since the standard base time known as "the epoch", namely January 1, 1970, 00:00:00 GMT.date
- the milliseconds since January 1, 1970, 00:00:00 GMT.@Deprecated public Date(int year, int month, int date)
Calendar.set(year + 1900, month, date)
or GregorianCalendar(year + 1900, month, date)
.Date
object and initializes it so that it represents midnight, local time, at the beginning of the day specified by the year
, month
, and date
arguments.year
- the year minus 1900.month
- the month between 0-11.date
- the day of the month between 1-31.@Deprecated public Date(int year, int month, int date, int hrs, int min)
Calendar.set(year + 1900, month, date, hrs, min)
or GregorianCalendar(year + 1900, month, date, hrs, min)
.Date
object and initializes it so that it represents the instant at the start of the minute specified by the year
, month
, date
, hrs
, and min
arguments, in the local time zone.year
- the year minus 1900.month
- the month between 0-11.date
- the day of the month between 1-31.hrs
- the hours between 0-23.min
- the minutes between 0-59.@Deprecated public Date(int year, int month, int date, int hrs, int min, int sec)
Calendar.set(year + 1900, month, date, hrs, min, sec)
or GregorianCalendar(year + 1900, month, date, hrs, min, sec)
.Date
object and initializes it so that it represents the instant at the start of the second specified by the year
, month
, date
, hrs
, min
, and sec
arguments, in the local time zone.year
- the year minus 1900.month
- the month between 0-11.date
- the day of the month between 1-31.hrs
- the hours between 0-23.min
- the minutes between 0-59.sec
- the seconds between 0-59.@Deprecated public Date(String s)
DateFormat.parse(String s)
.Date
object and initializes it so that it represents the date and time indicated by the string s
, which is interpreted as if by the parse(java.lang.String)
method.s
- a string representation of the date.IllegalArgumentException
- if s
cannot be interpreted as a representation of a date and time.public Object clone()
@Deprecated public static long UTC(int year, int month, int date, int hrs, int min, int sec)
Calendar.set(year + 1900, month, date, hrs, min, sec)
or GregorianCalendar(year + 1900, month, date, hrs, min, sec)
, using a UTC TimeZone
, followed by Calendar.getTime().getTime()
.Date
constructor with six arguments, except that the arguments are interpreted relative to UTC rather than to the local time zone. The time indicated is returned represented as the distance, measured in milliseconds, of that time from the epoch (00:00:00 GMT on January 1, 1970).year
- the year minus 1900.month
- the month between 0-11.date
- the day of the month between 1-31.hrs
- the hours between 0-23.min
- the minutes between 0-59.sec
- the seconds between 0-59.@Deprecated public static long parse(String s)
DateFormat.parse(String s)
.s
as a representation of a date and time. If the attempt is successful, the time indicated is returned represented as the distance, measured in milliseconds, of that time from the epoch (00:00:00 GMT on January 1, 1970). If the attempt fails, an IllegalArgumentException
is thrown. It accepts many syntaxes; in particular, it recognizes the IETF standard date syntax: "Sat, 12 Aug 1995 13:30:00 GMT". It also understands the continental U.S. time-zone abbreviations, but for general use, a time-zone offset should be used: "Sat, 12 Aug 1995 13:30:00 GMT+0430" (4 hours, 30 minutes west of the Greenwich meridian). If no time zone is specified, the local time zone is assumed. GMT and UTC are considered equivalent.
The string s
is processed from left to right, looking for data of interest. Any material in s
that is within the ASCII parenthesis characters (
and )
is ignored. Parentheses may be nested. Otherwise, the only characters permitted within s
are these ASCII characters:
and whitespace characters.abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ 0123456789,+-:/
A consecutive sequence of decimal digits is treated as a decimal number:
+
or -
and a year has already been recognized, then the number is a time-zone offset. If the number is less than 24, it is an offset measured in hours. Otherwise, it is regarded as an offset in minutes, expressed in 24-hour time format without punctuation. A preceding -
means a westward offset. Time zone offsets are always relative to UTC (Greenwich). Thus, for example, -5
occurring in the string would mean "five hours west of Greenwich" and +0430
would mean "four hours and thirty minutes east of Greenwich." It is permitted for the string to specify GMT
, UT
, or UTC
redundantly-for example, GMT-5
or utc+0430
. SimpleDateFormat
. 0
to 11
), unless a month has already been recognized, in which case it is regarded as a day of the month. A consecutive sequence of letters is regarded as a word and treated as follows:
AM
, ignoring case, is ignored (but the parse fails if an hour has not been recognized or is less than 1
or greater than 12
). PM
, ignoring case, adds 12
to the hour (but the parse fails if an hour has not been recognized or is less than 1
or greater than 12
). SUNDAY, MONDAY, TUESDAY,
WEDNESDAY, THURSDAY, FRIDAY
, or SATURDAY
, ignoring case, is ignored. For example, sat, Friday, TUE
, and Thurs
are ignored. JANUARY,
FEBRUARY, MARCH, APRIL, MAY, JUNE, JULY, AUGUST, SEPTEMBER,
OCTOBER, NOVEMBER
, or DECEMBER
, ignoring case, and considering them in the order given here, is recognized as specifying a month and is converted to a number (0
to 11
). For example, aug, Sept, april
, and NOV
are recognized as months. So is Ma
, which is recognized as MARCH
, not MAY
. GMT, UT
, or UTC
, ignoring case, is treated as referring to UTC. EST, CST, MST
, or PST
, ignoring case, is recognized as referring to the time zone in North America that is five, six, seven, or eight hours west of Greenwich, respectively. Any word that matches EDT, CDT,
MDT
, or PDT
, ignoring case, is recognized as referring to the same time zone, respectively, during daylight saving time.Once the entire string s has been scanned, it is converted to a time result in one of two ways. If a time zone or time-zone offset has been recognized, then the year, month, day of month, hour, minute, and second are interpreted in UTC and then the time-zone offset is applied. Otherwise, the year, month, day of month, hour, minute, and second are interpreted in the local time zone.
s
- a string to be parsed as a date.IllegalArgumentException
- if s
cannot be interpreted as a representation of a date and time.@Deprecated public int getYear()
Calendar.get(Calendar.YEAR) - 1900
.Date
object, as interpreted in the local time zone.@Deprecated public void setYear(int year)
Calendar.set(Calendar.YEAR, year + 1900)
.Date
object to be the specified value plus 1900. This Date
object is modified so that it represents a point in time within the specified year, with the month, date, hour, minute, and second the same as before, as interpreted in the local time zone. (Of course, if the date was February 29, for example, and the year is set to a non-leap year, then the new date will be treated as if it were on March 1.)year
- the year value.@Deprecated public int getMonth()
Calendar.get(Calendar.MONTH)
.Date
object. The value returned is between 0
and 11
, with the value 0
representing January.@Deprecated public void setMonth(int month)
Calendar.set(Calendar.MONTH, int month)
.Date
object is modified so that it represents a point in time within the specified month, with the year, date, hour, minute, and second the same as before, as interpreted in the local time zone. If the date was October 31, for example, and the month is set to June, then the new date will be treated as if it were on July 1, because June has only 30 days.month
- the month value between 0-11.@Deprecated public int getDate()
Calendar.get(Calendar.DAY_OF_MONTH)
.Date
object. The value returned is between 1
and 31
representing the day of the month that contains or begins with the instant in time represented by this Date
object, as interpreted in the local time zone.@Deprecated public void setDate(int date)
Calendar.set(Calendar.DAY_OF_MONTH, int date)
.Date
object to the specified value. This Date
object is modified so that it represents a point in time within the specified day of the month, with the year, month, hour, minute, and second the same as before, as interpreted in the local time zone. If the date was April 30, for example, and the date is set to 31, then it will be treated as if it were on May 1, because April has only 30 days.date
- the day of the month value between 1-31.@Deprecated public int getDay()
Calendar.get(Calendar.DAY_OF_WEEK)
.0
= Sunday, 1
= Monday, 2
= Tuesday, 3
= Wednesday, 4
= Thursday, 5
= Friday, 6
= Saturday) represents the day of the week that contains or begins with the instant in time represented by this Date
object, as interpreted in the local time zone.@Deprecated public int getHours()
Calendar.get(Calendar.HOUR_OF_DAY)
.Date
object. The returned value is a number (0
through 23
) representing the hour within the day that contains or begins with the instant in time represented by this Date
object, as interpreted in the local time zone.@Deprecated public void setHours(int hours)
Calendar.set(Calendar.HOUR_OF_DAY, int hours)
.Date
object to the specified value. This Date
object is modified so that it represents a point in time within the specified hour of the day, with the year, month, date, minute, and second the same as before, as interpreted in the local time zone.hours
- the hour value.@Deprecated public int getMinutes()
Calendar.get(Calendar.MINUTE)
.0
and 59
.@Deprecated public void setMinutes(int minutes)
Calendar.set(Calendar.MINUTE, int minutes)
.Date
object to the specified value. This Date
object is modified so that it represents a point in time within the specified minute of the hour, with the year, month, date, hour, and second the same as before, as interpreted in the local time zone.minutes
- the value of the minutes.@Deprecated public int getSeconds()
Calendar.get(Calendar.SECOND)
.0
and 61
. The values 60
and 61
can only occur on those Java Virtual Machines that take leap seconds into account.@Deprecated public void setSeconds(int seconds)
Calendar.set(Calendar.SECOND, int seconds)
.Date
to the specified value. This Date
object is modified so that it represents a point in time within the specified second of the minute, with the year, month, date, hour, and minute the same as before, as interpreted in the local time zone.seconds
- the seconds value.public long getTime()
Date
object.public void setTime(long time)
Date
object to represent a point in time that is time
milliseconds after January 1, 1970 00:00:00 GMT.time
- the number of milliseconds.public boolean before(Date when)
when
- a date.true
if and only if the instant of time represented by this Date
object is strictly earlier than the instant represented by when
; false
otherwise.NullPointerException
- if when
is null.public boolean after(Date when)
when
- a date.true
if and only if the instant represented by this Date
object is strictly later than the instant represented by when
; false
otherwise.NullPointerException
- if when
is null.public boolean equals(Object obj)
true
if and only if the argument is not null
and is a Date
object that represents the same point in time, to the millisecond, as this object. Thus, two Date
objects are equal if and only if the getTime
method returns the same long
value for both.
public int compareTo(Date anotherDate)
compareTo
in interface Comparable<Date>
anotherDate
- the Date
to be compared.0
if the argument Date is equal to this Date; a value less than 0
if this Date is before the Date argument; and a value greater than 0
if this Date is after the Date argument.NullPointerException
- if anotherDate
is null.public int hashCode()
long
value returned by the getTime()
method. That is, the hash code is the value of the expression: (int)(this.getTime()^(this.getTime() >>> 32))
public String toString()
Date
object to a String
of the form: where:dow mon dd hh:mm:ss zzz yyyy
dow
is the day of the week (Sun, Mon, Tue, Wed,
Thu, Fri, Sat
). mon
is the month (Jan, Feb, Mar, Apr, May, Jun,
Jul, Aug, Sep, Oct, Nov, Dec
). dd
is the day of the month (01
through 31
), as two decimal digits. hh
is the hour of the day (00
through 23
), as two decimal digits. mm
is the minute within the hour (00
through 59
), as two decimal digits. ss
is the second within the minute (00
through 61
, as two decimal digits. zzz
is the time zone (and may reflect daylight saving time). Standard time zone abbreviations include those recognized by the method parse
. If time zone information is not available, then zzz
is empty - that is, it consists of no characters at all. yyyy
is the year, as four decimal digits. @Deprecated public String toLocaleString()
DateFormat.format(Date date)
.Date
object in an implementation-dependent form. The intent is that the form should be familiar to the user of the Java application, wherever it may happen to be running. The intent is comparable to that of the "%c
" format supported by the strftime()
function of ISO C.@Deprecated public String toGMTString()
DateFormat.format(Date date)
, using a GMT TimeZone
.Date
object of the form: where:d mon yyyy hh:mm:ss GMT
1
through 31
), as one or two decimal digits. Jan, Feb, Mar, Apr, May, Jun, Jul,
Aug, Sep, Oct, Nov, Dec
). 00
through 23
), as two decimal digits. 00
through 59
), as two decimal digits. 00
through 61
), as two decimal digits. GMT
" to indicate Greenwich Mean Time. The result does not depend on the local time zone.
@Deprecated public int getTimezoneOffset()
-(Calendar.get(Calendar.ZONE_OFFSET) +
Calendar.get(Calendar.DST_OFFSET)) / (60 * 1000)
.Date
object. For example, in Massachusetts, five time zones west of Greenwich:
because on February 14, 1996, standard time (Eastern Standard Time) is in use, which is offset five hours from UTC; but:new Date(96, 1, 14).getTimezoneOffset() returns 300
because on June 1, 1996, daylight saving time (Eastern Daylight Time) is in use, which is offset only four hours from UTC.new Date(96, 5, 1).getTimezoneOffset() returns 240
This method produces the same result as if it computed:
(this.getTime() - UTC(this.getYear(), this.getMonth(), this.getDate(), this.getHours(), this.getMinutes(), this.getSeconds())) / (60 * 1000)
public static Date from(Instant instant)
Date
from an Instant
object. Instant
uses a precision of nanoseconds, whereas Date
uses a precision of milliseconds. The conversion will truncate any excess precision information as though the amount in nanoseconds was subject to integer division by one million.
Instant
can store points on the time-line further in the future and further in the past than Date
. In this scenario, this method will throw an exception.
instant
- the instant to convertDate
representing the same point on the time-line as the provided instantNullPointerException
- if instant
is null.IllegalArgumentException
- if the instant is too large to represent as a Date
public Instant toInstant()
Date
object to an Instant
. The conversion creates an Instant
that represents the same point on the time-line as this Date
.
Date
object
© 1993, 2023, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/util/Date.html
Calendar.set(year + 1900, month, date)
orGregorianCalendar(year + 1900, month, date)
.