Do you absolutely have to use java.util.Date? I would thoroughly recommend that you use Joda Time or the java.time package from Java 8 instead. In particular, while Date and Calendar always represent a particular instant in time, with no such concept as "just a date", Joda Time does have a type representing this (LocalDate). Your code will be much clearer if you're able to use types which represent what you're actually trying to do.

There are many, many other reasons to use Joda Time or java.time instead of the built-in java.util types - they're generally far better APIs. You can always convert to/from a java.util.Date at the boundaries of your own code if you need to, e.g. for database interaction.

You could use a Calendar to solve this:

Calendar cal = Calendar.getInstance();
cal.setTime(yourDate);
cal.set(Calendar.HOUR, 0);
cal.set(Calendar.MINUTE, 0);
cal.set(Calendar.SECOND, 0);
cal.set(Calendar.MILLISECOND, 0);
Date desiredDate = cal.getTime();

A java.util.Date object is a kind of timestamp - it contains a number of milliseconds since January 1, 1970, 00:00:00 UTC. So you can't use a standard Date object to contain just a day / month / year, without a time.

As far as I know, there's no really easy way to compare dates by only taking the date (and not the time) into account in the standard Java API. You can use class Calendar and clear the hour, minutes, seconds and milliseconds:

Calendar cal = Calendar.getInstance();
cal.clear(Calendar.HOUR_OF_DAY);
cal.clear(Calendar.AM_PM);
cal.clear(Calendar.MINUTE);
cal.clear(Calendar.SECOND);
cal.clear(Calendar.MILLISECOND);

Do the same with another Calendar object that contains the date that you want to compare it to, and use the after() or before() methods to do the comparison.

As explained into the Javadoc of java.util.Calendar.clear(int field):

The HOUR_OF_DAY, HOUR and AM_PM fields are handled independently and the the resolution rule for the time of day is applied. Clearing one of the fields doesn't reset the hour of day value of this Calendar. Use set(Calendar.HOUR_OF_DAY, 0) to reset the hour value.

edit - The answer above is from 2010; in Java 8, there is a new date and time API in the package java.time which is much more powerful and useful than the old java.util.Date and java.util.Calendar classes. Use the new date and time classes instead of the old ones.

What's the best way to get the current date/time in Java?

There is no "best" way.

It depends on what form of date / time you want:

• If you want the date / time as a single numeric value, then System.currentTimeMillis() gives you that, expressed as the number of milliseconds after the UNIX epoch (as a Java long). This value is a delta from a UTC time-point, and is independent of the local time-zone¹.

• If you want the date / time in a form that allows you to access the components (year, month, etc) numerically, you could use one of the following:

  • new Date() gives you a Date object initialized with the current date / time. The problem is that the Date API methods are mostly flawed ... and deprecated.

  • Calendar.getInstance() gives you a Calendar object initialized with the current date / time, using the default Locale and TimeZone. Other overloads allow you to use a specific Locale and/or TimeZone. Calendar works ... but the APIs are still cumbersome.

  • new org.joda.time.DateTime() gives you a Joda-time object initialized with the current date / time, using the default time zone and chronology. There are lots of other Joda alternatives ... too many to describe here. (But note that some people report that Joda time has performance issues.; e.g. https://stackoverflow.com/questions/6280829.)

  • in Java 8, calling java.time.LocalDateTime.now() and java.time.ZonedDateTime.now() will give you representations² for the current date / time.

Prior to Java 8, most people who know about these things recommended Joda-time as having (by far) the best Java APIs for doing things involving time point and duration calculations.

With Java 8 and later, the standard java.time package is recommended. Joda time is now considered "obsolete", and the Joda maintainers are recommending that people migrate³.

Note: the Calendar, org.joda.time and java.time solutions can use either the platform's default timezone or an explicit timezone provided via constructor arguments. Generally, using an explicit timezone rather than the default zone will make your application's behavior more predictable / less susceptible to problems if (for example) you redeploy to a data center in a different timezone.

But no matter what you do, you (and maybe your application) should be aware that the timezone of the user, your service and the data center can all be different. The concept of the "current date/time" is complicated.

^{1 - System.currentTimeMillis() gives the "system" time. While it is normal practice for the system clock to be set to (nominal) UTC, there will be a difference (a delta) between the local UTC clock and true UTC. The size of the delta depends on how well (and how often) the system's clock is synced with UTC.
2 - Note that LocalDateTime doesn't include a time zone. As the javadoc says: "It cannot represent an instant on the time-line without additional information such as an offset or time-zone."
3 - Note: your Java 8 code won't break if you don't migrate, but the Joda codebase may eventually stop getting bug fixes and other patches. As of 2020-02, an official "end of life" for Joda has not been announced, and the Joda APIs have not been marked as Deprecated.}

Calendar cal = Calendar.getInstance();
cal.set(Calendar.HOUR_OF_DAY, 0);
cal.set(Calendar.MINUTE, 0);
cal.set(Calendar.SECOND, 0);
cal.set(Calendar.MILLISECOND, 0);
currentDate = cal.getTimeInMillis();

Be carefull on the timezone of your Calendar.