Comparing two Calendar dates

Question

No question. Just a comment with code example.
Yesterday I was having issues comparing two Calendar dates. They looked equal in my println statement, but they failed the test. The solution evaded my cafeine intensified brain for hours. Then it hit me. Print out the time in milliseconds and see if the numbers were the same. Nope. Why?
The problem was that in the real world, you get dates from all over the place, not just cooked up for a text book example. (Don't you just hate those text book examples in their unrealistic world?) Anyway, I was getting a date from an HTML form and a data from a database and comparing the two once I had converted them both to a Calendar object. This seemed a reasonable choice.
Well, the java.sql.Date that the Oracle driver returned which was converted to a java.util.Date was fine. I ran this into a Calendar with the call calS.setTime(dbDate). The form date was split into fields and put into a difference Calendar obj with the call calF.set(fYear, fMonth, fDay, 0, 0, 0). This too seemed reasonable. Then a call to calS.equls(calF) resulted in a false even though the actual dates were in fact the same.
The problem was with the time. The java.sql.Date (calS) had a time of 00:00:00 which was fine. The calendar from the form also had 00:00:00 for a time since I initialized it with zeros. Hummmmm. Now what? As mentioned before, I decided to print out the actuall time in milliseconds and that gave me my answer. The two calendars were off by only milliseconds, but that's why. You see, the equals method of Calendar compares two dates/time in milliseconds. You can see this in the source for yourself. It's not difficult to read at all. Download and open the api source file, src.zip, and locate Calendar.java in the java.util directory.
The fix was to add calF.set(Calendar.MILLISECOND, 0) and calS.set(Calendar.MILLISECOND, 0) to zero out the milliseconds in each Calendar object. That did the trick. Here's example code of the problem (test1) and the solution (test2). I tried to simulate as close to real world as possible. If you have a better solution or I've made some error, please let me know. I'm always looking for better ways.
Main.java
import java.util.Calendar;
import java.util.Date;
import java.text.SimpleDateFormat;
public class Main {
    private int fYear = 2003;
    private int fMonth = 3;  // march
    private int fDay = 14;
    public static void main(String[] args) {
        Main main = new Main();
        main.test1();
        main.test2();
    public void test1() {
        SimpleDateFormat df = new SimpleDateFormat();
        // get the date from the form
        Calendar calF = Calendar.getInstance();
        calF.set(fYear, fMonth-1, fDay, 0, 0, 0);  // month starts at 0 - so march would be 2
        System.out.println("From form date:     [" + df.format(calF.getTime()) + "] [" + calF.getTimeInMillis() + "]");
        // simulate other activity in the app
        try {
            Thread.sleep(5000);
        catch (Exception ex) {
            ex.printStackTrace();
        // get the Date from the shared object which comes from a database (java.sql.Date)
        // the return is java.util.Date
        // convert to a Calendar
        SharedObject so = new SharedObject();
        Date myDate = so.getTheDate();
        Calendar calS = Calendar.getInstance();
        calS.setTime(myDate);
        System.out.println("Shared Object date: [" + df.format(calS.getTime()) + "] [" + calS.getTimeInMillis() + "]");
        // compare the two calendars for equality
        if (calS.equals(calF)) {
            System.out.println("The same");
        else {
            System.out.println("NOT the same");
    public void test2() {
        SimpleDateFormat df = new SimpleDateFormat();
        // get the date from the form
        Calendar calF = Calendar.getInstance();
        calF.set(fYear, fMonth-1, fDay, 0, 0, 0);
        calF.set(Calendar.MILLISECOND, 0);  // the magic bean
        System.out.println("From form date:     [" + df.format(calF.getTime()) + "] [" + calF.getTimeInMillis() + "]");
        // simulate other activity in the app
        try {
            Thread.sleep(5000);
        catch (Exception ex) {
            ex.printStackTrace();
        // get the Date from the shared object which comes from a database (java.sql.Date)
        // the return is java.util.Date
        // convert to a Calendar
        SharedObject so = new SharedObject();
        Date myDate = so.getTheDate();
        Calendar calS = Calendar.getInstance();
        calS.setTime(myDate);  // just to be safe
        calF.set(Calendar.MILLISECOND, 0);
        System.out.println("Shared Object date: [" + df.format(calS.getTime()) + "] [" + calS.getTimeInMillis() + "]");
        // compare the two calendars for equality
        if (calS.equals(calF)) {
            System.out.println("The same");
        else {
            System.out.println("NOT the same");
SharedObject.java
public class SharedObject {
    public java.util.Date getTheDate() {
        java.util.Date d = null;
        try {
            java.sql.Date s = java.sql.Date.valueOf("2003-3-14");  // this march is converted internally
            d = (java.util.Date)s;
        catch (Exception ex) {
            ex.printStackTrace();
        return d;
} The output
From form date:     [3/14/03 12:00 AM] [1047621600296]
Shared Object date: [3/14/03 12:00 AM] [1047621600000]
NOT the same
From form date:     [3/14/03 12:00 AM] [1047621600000]
Shared Object date: [3/14/03 12:00 AM] [1047621600000]
The same

Answer 1

So your post boils down to the fact that Calendar's set(year, month, day, hour, minute, second) method doesn't change the milliseconds fraction?
Given that there is this method, I guess it would be nice if there was a method that simultaneously set all fields, but the API does state:
Previous values of other fields are retained. If this is not desired, call clear() first.