java.util.Date;

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:

     http://tycho.usno.navy.mil
 

and their definitions of "Systems of Time" at:

     http://tycho.usno.navy.mil/systime.html
 

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 y - 1900.
• A month is represented by an integer from 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 61; the values 60 and 61 occur only for leap seconds and even then only in Java implementations that actually track leap seconds correctly. Because of the manner in which leap seconds are currently introduced, it is extremely unlikely that two leap seconds will occur in the same minute, but this specification follows the date and time conventions for ISO C.

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.

Since:

JDK1.0

See Also:

DateFormat, Calendar, TimeZone, Serialized Form

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Constructor Summary

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(int year, int month, int date)           Deprecated. As of JDK version 1.1, replaced by Calendar.set(year + 1900, month, date) or GregorianCalendar(year + 1900, month, date).

Date(int year, int month, int date, int hrs, int min)           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(int year, int month, int date, int hrs, int min, int sec)           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(long 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(String s)           Deprecated. As of JDK version 1.1, replaced by DateFormat.parse(String s).

Method Summary
boolean	after(Date when)           Tests if this date is after the specified date.
boolean	before(Date when)           Tests if this date is before the specified date.
Object	clone()           Return a copy of this object.
int	compareTo(Date anotherDate)           Compares two Dates for ordering.
int	compareTo(Object o)           Compares this Date to another Object.
boolean	equals(Object obj)           Compares two dates for equality.
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(String s)           Deprecated. As of JDK version 1.1, replaced by DateFormat.parse(String s).
void	setDate(int date)           Deprecated. As of JDK version 1.1, replaced by Calendar.set(Calendar.DAY_OF_MONTH, int date).
void	setHours(int hours)           Deprecated. As of JDK version 1.1, replaced by Calendar.set(Calendar.HOUR_OF_DAY, int hours).
void	setMinutes(int minutes)           Deprecated. As of JDK version 1.1, replaced by Calendar.set(Calendar.MINUTE, int minutes).
void	setMonth(int month)           Deprecated. As of JDK version 1.1, replaced by Calendar.set(Calendar.MONTH, int month).
void	setSeconds(int seconds)           Deprecated. As of JDK version 1.1, replaced by Calendar.set(Calendar.SECOND, int seconds).
void	setTime(long time)           Sets this Date object to represent a point in time that is time milliseconds after January 1, 1970 00:00:00 GMT.
void	setYear(int year)           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.
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(int year, int month, int date, int hrs, int min, int sec)           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().

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait