Difference between Date class in Package java.util & Package java.sql

Question

In java, both the java.util and the java.sql package contain a Date class, So what is the difference between them?

If one

Answer 1

These answers seem to be partially outdated.

I just read a little API Code (Java Version 1.8.0_91) and found this in java.sql.Date:

/**
 * Creates a date which corresponds to the day determined by the supplied
 * milliseconds time value {@code theDate}.
 *
 * @param theDate
 *            a time value in milliseconds since the epoch - January 1 1970
 *            00:00:00 GMT. The time value (hours, minutes, seconds,
 *            milliseconds) stored in the {@code Date} object is adjusted to
 *            correspond to 00:00:00 GMT on the day determined by the supplied
 *            time value.
 */
public Date(long theDate) {
    super(normalizeTime(theDate));
}

/*
 * Private method which normalizes a Time value, removing all low
 * significance digits corresponding to milliseconds, seconds, minutes and
 * hours, so that the returned Time value corresponds to 00:00:00 GMT on a
 * particular day.
 */
private static long normalizeTime(long theTime) {
    return theTime;
}

The method for normalizing the time is still there and even the comment says that the time will be normalized to 00:00:00 GMT but it does nothing. For some reason they removed the normalization, wich means, that a java.sql.Date contains just like a java.util.Date just the number of milliseconds since 1.1.1970. So there is a time component but it is not displayed externally.

For example the code

java.util.Date utilDate = new java.util.Date();
java.sql.Date sqlDate = new java.sql.Date(Calendar.getInstance().getTimeInMillis())

System.out.println(utilDate);
System.out.println(sqlDate);

produces the output

Thu Jun 02 13:17:35 CEST 2016
2016-06-02

So be careful with sql dates and do not handle them like they would just contain a Date and no time information. For example:

java.sql.Date sqlDate1 = new java.sql.Date(Calendar.getInstance().getTimeInMillis());
java.sql.Date sqlDate2 = new java.sql.Date(Calendar.getInstance().getTimeInMillis());

System.out.println(sqlDate1);
System.out.println(sqlDate2);
System.out.println(sqlDate1.equals(sqlDate2));
System.out.println(sqlDate1.toString().equals(sqlDate2.toString()));

prints:

2016-06-02
2016-06-02
false
true