Date object represents a precise moment in time, down to the millisecond.
Dates are represented as a long that counts the number of milliseconds since midnight, January 1, 1970, Greenwich Meantime. Does this have a year 2000 problem? If so in what year?
To create a Date object for the current date and time use the noargs Date() constructor like this:
Date now = new Date();
To create a Date object for a specific time, pass the number of milliseconds
since midnight, January 1, 1970, Greenwich Meantime to the constructor, like this:
Date midnight_jan2_1970 = new Date(24L*60L*60L*1000L);
You can return the number of milliseconds in the Date as a long, using the
getTime() method. For example,
to time a block of code, you might do this
Date d1 = new Date();
// timed code goes here
Date d2 = new Date();
long elapsed_time = d2.getTime() - d1.getTime();
System.out.println("That took " + elapsed_time + " milliseconds");
Date by passing the new date as a number of milliseconds
since midnight, January 1, 1970, GMT, to the setTime() method, like this:
Date midnight_jan2_1970 = new Date();
midnight_jan2_1970.setTime(24L*60L*60L*1000L);
before() method returns true if this Date is before the Date argument, false if it's not. For example
if (midnight_jan2_1970.before(new Date())) {
after() method returns true if this Date is after the Date argument, false if it's not. For example
if (midnight_jan2_1970.after(new Date())) {
Date class also has the usual hashCode(), equals(), and
toString() methods.