The class 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 U.S. Naval Observatory, particularly
the Directorate of Time at:
and their definitions of "Systems of Time" at:
In all methods of class Date that accept or return
year, month, date, hours, minutes, and seconds values, the
following representations are used:
A year y is represented by the integer
A month is represented by an integer form 0 to 11; 0 is January,
1 is February, and so forth; thus 11 is December.
A date (day of month) is represented by an integer from 1 to 31
in the usual manner.
An hour is represented by an integer from 0 to 23. Thus, the hour
from midnight to 1 a.m. is hour 0, and the hour from noon to 1
p.m. is hour 12.
A minute is represented by an integer from 0 to 59 in the usual manner.
A second is represented by an integer from 0 to 60; the value 60 occurs
only for leap seconds and even then only in Java implementations that
actually track leap seconds correctly.
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.
Allocates a Date object and initializes it so that
it represents the specified hour, minute, and second, local time
of the date specified by the year, month,
date, hrs, min, and
public static long UTC(int year,
Note: UTC() is 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().
Determines the date and time based on the arguments. The
arguments are interpreted in UTC, not 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.
the number of milliseconds since January 1, 1970, 00:00:00 GMT for
the date and time specified by the arguments.
Note: parse() is deprecated.As of JDK version 1.1,
replaced by DateFormat.parse(String s).
Given a string representing a time, parse it and return the time
value. This method recognizes most standard syntaxes.
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.
s - a string to be parsed as a date.
the number of milliseconds since January 1, 1970, 00:00:00 GMT
represented by the string argument.
Note: getSeconds() is deprecated.As of JDK version 1.1,
replaced by Calendar.get(Calendar.SECOND).
Returns the number of seconds past the minute represented by this date.
The value returned is between 0 and 60. The
value 60 can only occur on those Java Virtual Machines that
take leap seconds into account.
the number of seconds past the minute represented by this date.
Note: toLocaleString() is deprecated.As of JDK version 1.1,
replaced by DateFormat.format(Date date).
Creates a string representation of this date 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.
a string representation of this date, using the locale
Note: getTimezoneOffset() is deprecated.As of JDK version 1.1,
replaced by Calendar.get(Calendar.ZONE_OFFSET) +
Returns the local time-zone offset. The time-zone offset is
the number of minutes that must be added to GMT to give the local
time zone. This value includes the correction, if necessary, for
daylight saving time.
the time-zone offset, in minutes, for the current locale.
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