You probably have some other "Date" class imported somewhere (or you have a Date class in you package, which does not need to be imported). With "import java.util.*" you are using the "other" Date. In this case it's best to explicitly specify java.util.Date in the code.
Or better, try to avoid naming your classes "Date".
Answer from sleske on Stack OverflowYou probably have some other "Date" class imported somewhere (or you have a Date class in you package, which does not need to be imported). With "import java.util.*" you are using the "other" Date. In this case it's best to explicitly specify java.util.Date in the code.
Or better, try to avoid naming your classes "Date".
The toString() implementation of java.util.Date does not depend on the way the class is imported. It always returns a nice formatted date.
The toString() you see comes from another class.
Specific import have precedence over wildcard imports.
in this case
import other.Date
import java.util.*
new Date();
refers to other.Date and not java.util.Date.
The odd thing is that
import other.*
import java.util.*
Should give you a compiler error stating that the reference to Date is ambiguous because both other.Date and java.util.Date matches.
You try to do something impossible. You should create a class and in a method in this class, you should make these operations. In the example below, you make these operations in a main method in your class. Main method is where the program starts.
In addition to these points, if your class is in a package, you should define it at the very beginning of the class. For example, your package is called as myPackage, you should add it to your code like that below;
For example, you creates a class Foo in a package myPackage.
package myPackage;
import java.util.Date;
public class Foo {
public static void main(String args[]) {
// You create a new date object and assign it to the sysdate
Date sysdate = new Date();
// You are now displaying your time and date using toString()
System.out.println(sysdate.toString());
}
}
The instructions in Java can't be outside classes. So your instructions
Date sysdate = new Date();
System.out.println(sysdate);
Should be in a method (For example, in the main), and the method must be declared in a class. As far as I know, import and package instructions are the only ones which have to be before the class definition.
Note also that the file where the class is written must have the same name of the class, for instance, the example DateDemo must be save in a file called DateDemo.java.
Gotcha: passing 2 as month may give you unexpected result: in Calendar API, month is zero-based. 2 actually means March.
I don't know what is an "easy" way that you are looking for as I feel that using Calendar is already easy enough.
Remember to use correct constants for month:
Date date = new GregorianCalendar(2014, Calendar.FEBRUARY, 11).getTime();
Another way is to make use of DateFormat, which I usually have a util like this:
public static Date parseDate(String date) {
try {
return new SimpleDateFormat("yyyy-MM-dd").parse(date);
} catch (ParseException e) {
return null;
}
}
so that I can simply write
Date myDate = parseDate("2014-02-14");
Yet another alternative I prefer: Don't use Java Date/Calendar anymore. Switch to JODA Time or Java Time (aka JSR310, available in JDK 8+). You can use LocalDate to represent a date, which can be easily created by
LocalDate myDate =LocalDate.parse("2014-02-14");
// or
LocalDate myDate2 = new LocalDate(2014, 2, 14);
// or, in JDK 8+ Time
LocalDate myDate3 = LocalDate.of(2014, 2, 14);
tl;dr
LocalDate.of( 2014 , 2 , 11 )
If you insist on using the terrible old java.util.Date class, convert from the modern java.time classes.
java.util.Date // Terrible old legacy class, avoid using. Represents a moment in UTC.
.from( // New conversion method added to old classes for converting between legacy classes and modern classes.
LocalDate // Represents a date-only value, without time-of-day and without time zone.
.of( 2014 , 2 , 11 ) // Specify year-month-day. Notice sane counting, unlike legacy classes: 2014 means year 2014, 1-12 for Jan-Dec.
.atStartOfDay( // Let java.time determine first moment of the day. May *not* start at 00:00:00 because of anomalies such as Daylight Saving Time (DST).
ZoneId.of( "Africa/Tunis" ) // Specify time zone as `Continent/Region`, never the 3-4 letter pseudo-zones like `PST`, `EST`, or `IST`.
) // Returns a `ZonedDateTime`.
.toInstant() // Adjust from zone to UTC. Returns a `Instant` object, always in UTC by definition.
) // Returns a legacy `java.util.Date` object. Beware of possible data-loss as any microseconds or nanoseconds in the `Instant` are truncated to milliseconds in this `Date` object.
Details
If you want "easy", you should be using the new java.time package in Java 8 rather than the notoriously troublesome java.util.Date & .Calendar classes bundled with Java.
java.time
The java.time framework built into Java 8 and later supplants the troublesome old java.util.Date/.Calendar classes.
Date-only
A LocalDate class is offered by java.time to represent a date-only value without any time-of-day or time zone. You do need a time zone to determine a date, as a new day dawns earlier in Paris than in Montréal for example. The ZoneId class is for time zones.
ZoneId zoneId = ZoneId.of( "Asia/Singapore" );
LocalDate today = LocalDate.now( zoneId );
Dump to console:
System.out.println ( "today: " + today + " in zone: " + zoneId );
today: 2015-11-26 in zone: Asia/Singapore
Or use a factory method to specify the year, month, day.
LocalDate localDate = LocalDate.of( 2014 , Month.FEBRUARY , 11 );
localDate: 2014-02-11
Or pass a month number 1-12 rather than a DayOfWeek enum object.
LocalDate localDate = LocalDate.of( 2014 , 2 , 11 );
Time zone
A LocalDate has no real meaning until you adjust it into a time zone. In java.time, we apply a time zone to generate a ZonedDateTime object. That also means a time-of-day, but what time? Usually makes sense to go with first moment of the day. You might think that means the time 00:00:00.000, but not always true because of Daylight Saving Time (DST) and perhaps other anomalies. Instead of assuming that time, we ask java.time to determine the first moment of the day by calling atStartOfDay.
Specify a proper time zone name in the format of continent/region, such as America/Montreal, Africa/Casablanca, or Pacific/Auckland. Never use the 3-4 letter abbreviation such as EST or IST as they are not true time zones, not standardized, and not even unique(!).
ZoneId zoneId = ZoneId.of( "Asia/Singapore" );
ZonedDateTime zdt = localDate.atStartOfDay( zoneId );
zdt: 2014-02-11T00:00+08:00[Asia/Singapore]
UTC
For back-end work (business logic, database, data storage & exchange) we usually use UTC time zone. In java.time, the Instant class represents a moment on the timeline in UTC. An Instant object can be extracted from a ZonedDateTime by calling toInstant.
Instant instant = zdt.toInstant();
instant: 2014-02-10T16:00:00Z
Convert
You should avoid using java.util.Date class entirely. But if you must interoperate with old code not yet updated for java.time, you can convert back-and-forth. Look to new conversion methods added to the old classes.
java.util.Date d = java.util.from( instant ) ;
…and…
Instant instant = d.toInstant() ;
About java.time
The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.
To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.
The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.
You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes. Hibernate 5 & JPA 2.2 support java.time.
Where to obtain the java.time classes?
- Java SE 8, Java SE 9, Java SE 10, Java SE 11, and later - Part of the standard Java API with a bundled implementation.
- Java 9 brought some minor features and fixes.
- Java SE 6 and Java SE 7
- Most of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport.
- Android
- Later versions of Android (26+) bundle implementations of the java.time classes.
- For earlier Android (<26), a process known as API desugaring brings a subset of the java.time functionality not originally built into Android.
- If the desugaring does not offer what you need, the ThreeTenABP project adapts ThreeTen-Backport (mentioned above) to Android. See How to use ThreeTenABP….
UPDATE: The Joda-Time library is now in maintenance mode, and advises migration to the java.time classes. I am leaving this section in place for history.
Joda-Time
For one thing, Joda-Time uses sensible numbering so February is 2 not 1. Another thing, a Joda-Time DateTime truly knows its assigned time zone unlike a java.util.Date which seems to have time zone but does not.
And don't forget the time zone. Otherwise you'll be getting the JVM’s default.
DateTimeZone timeZone = DateTimeZone.forID( "Asia/Singapore" );
DateTime dateTimeSingapore = new DateTime( 2014, 2, 11, 0, 0, timeZone );
DateTime dateTimeUtc = dateTimeSingapore.withZone( DateTimeZone.UTC );
java.util.Locale locale = new java.util.Locale( "ms", "SG" ); // Language: Bahasa Melayu (?). Country: Singapore.
String output = DateTimeFormat.forStyle( "FF" ).withLocale( locale ).print( dateTimeSingapore );
Dump to console…
System.out.println( "dateTimeSingapore: " + dateTimeSingapore );
System.out.println( "dateTimeUtc: " + dateTimeUtc );
System.out.println( "output: " + output );
When run…
dateTimeSingapore: 2014-02-11T00:00:00.000+08:00
dateTimeUtc: 2014-02-10T16:00:00.000Z
output: Selasa, 2014 Februari 11 00:00:00 SGT
Conversion
If you need to convert to a java.util.Date for use with other classes…
java.util.Date date = dateTimeSingapore.toDate();
