Thursday 14 March 2013

java.util Date


java.util
Date

Declaration
public class Date
java.lang.Object
|
+--java.util.Date
Description
The class Date represents a specific instant in time, with millisecond precision.
This class has been subset for the J2ME based on the JDK 1.3 Date class. Many methods and variables have
been pruned, and other methods simplified, in an effort to reduce the size of this class.
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 = 24x60x60 = 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.


Constructors
Date()
Date(long date)
Methods
boolean equals(java.lang.Object obj)
long getTime()
int hashCode()
void setTime(long time)
java.lang.String toString()


Methods inherited from class Object
getClass(), notify(), notifyAll(), wait(), wait(), wait()


Constructors
Date()
Declaration:
public Date()
Description:
Allocates a Date object and initializes it to represent the current time specified number of milliseconds
since the standard base time known as “the epoch”, namely January 1, 1970, 00:00:00 GMT.
See Also: java.lang.System.currentTimeMillis()
Date(long)
Declaration:
public Date(long date)
Description:
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.
Parameters:
date - the milliseconds since January 1, 1970, 00:00:00 GMT.
See Also: java.lang.System.currentTimeMillis()
Methods
getTime()
Declaration:
public long getTime()
Description:
Returns the number of milliseconds since January 1, 1970, 00:00:00 GMT represented by this Date object.
Returns: the number of milliseconds since January 1, 1970, 00:00:00 GMT represented by this date.
See Also: setTime(long)
setTime(long)
Declaration:
public void setTime(long time)
Description:
Sets this Date object to represent a point in time that is time milliseconds after January 1, 1970 00:00:00
GMT.
Parameters:
time - the number of milliseconds.
See Also: getTime()


equals(Object)
Declaration:
public boolean equals(java.lang.Object obj)
Description:
Compares two dates for equality. The result is 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.
Overrides: equals in class Object
Parameters:
obj - the object to compare with.
Returns: true if the objects are the same; false otherwise.
See Also: getTime()
hashCode()
Declaration:
public int hashCode()
Description:
Returns a hash code value for this object. The result is the exclusive OR of the two halves of the primitive
long value returned by the getTime() method. That is, the hash code is the value of the expression:
(int)(this.getTime()^(this.getTime() >>> 32))
Overrides: hashCode in class Object
Returns: a hash code value for this object.
toString()
Declaration:
public java.lang.String toString()
Description:
Converts this Date object to a String of the form:
dow mon dd hh:mm:ss zzz yyyy
where:
• 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 savings time). 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.

toString()
268
Overrides: toString in class Object
Returns: a string representation of this date.
Since: CLDC 1.1






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