public class Date extends Object implements Cloneable, Comparable<Date>
Daterepresents a specific instant in time, with millisecond precision.
This class has been subset for Java ME based on the JDK 1.7 Date class. Many methods and variables have been pruned, and other methods simplified, in an effort to reduce the size of this class.
As of JDK 1.1, the
Calendar class should be used to convert between dates and time
The corresponding methods in
Date are deprecated.
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:
|Constructor and Description|
|Modifier and Type||Method and Description|
Return a copy of this object.
Compares two Dates for ordering.
Compares two dates for equality.
Returns the number of milliseconds since January 1, 1970, 00:00:00 GMT represented by this Date object.
Returns a hash code value for this object.
Dateobject and initializes it so that it represents the time at which it was allocated, measured to the nearest millisecond.
public Date(long date)
Dateobject 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.
public Object clone()
public int compareTo(Date anotherDate)
Dateto be compared.
0if the argument Date is equal to this Date; a value less than
0if this Date is before the Date argument; and a value greater than
0if this Date is after the Date argument.
public boolean equals(Object obj)
trueif and only if the argument is not
nulland is a
Dateobject that represents the same point in time, to the millisecond, as this object.
Date objects are equal if and only if the
getTime method returns the same
value for both.
public long getTime()
public int hashCode()
getTime()method. That is, the hash code is the value of the expression:
(int)(this.getTime()^(this.getTime() >>> 32))
public void setTime(long time)
Dateobject to represent a point in time that is
timemilliseconds after January 1, 1970 00:00:00 GMT.
time- the number of milliseconds.
public String toString()
Dateobject to a
Stringof the form:
where:dow mon dd hh:mm:ss zzz yyyy
Copyright (c) 2014, Oracle and/or its affiliates. All Rights Reserved. Use of this specification is subject to license terms.