Android SimpleDateFormat returning incorrect time between midnight and 1am

Question

SOLVED I have found that between midnight and 1am my device returns a time 1 hour later (the other 23 hours a day it returns correctly). More weirdly it returns correctly if I use kk instead of HH (though the resulting string is no use to me)

Code I am running: (in this instance strFormat matches the hardcoded string in df3)

SimpleDateFormat df = new SimpleDateFormat(strFormat, Locale.US);
SimpleDateFormat df2 = new SimpleDateFormat("yyyy-MM-dd kk:mm", Locale.US);
SimpleDateFormat df3 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS", Locale.US);

Date d = c.getTime();
String s = d.toString();
String ret = df.format(c.getTime());
String ret2 = df.format(new Date(System.currentTimeMillis()));
String ret3 = df2.format(c.getTime());
String ret4 = df3.format(c.getTime());
String r1 = ""+c.get(Calendar.HOUR);

These return:

s = "Thu Jan 07 00:39:32 GMT-11:00 2016"
ret = "2016-01-07 01:39:32"
ret2 = "2016-01-07 01:39:32"
ret3 = "2016-01-07 24:39"
ret4 = "2016-01-07 01:39:32.525"
r1 = "0"

After 1am these return:

s = "Thu Jan 07 01:07:09 GMT-11:00 2016"
ret = "2016-01-07 01:07:09"
ret2 = "2016-01-07 01:07:09"
ret3 = "2016-01-07 01:07"
ret4 = "2016-01-07 01:07:09.606"
r1 = "1"

Any help in what I have done wrong/what is going wrong greatly appreciated.

UPDATE

changing code to:

SimpleDateFormat df = new SimpleDateFormat(strFormat, Locale.US);
        df.setTimeZone(TimeZone.getTimeZone("GMT"));
        SimpleDateFormat df2 = new SimpleDateFormat("yyyy-MM-dd kk:mm zzz", Locale.US);
        df2.setTimeZone(TimeZone.getTimeZone("GMT"));
        SimpleDateFormat df3 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS zzz", Locale.US);
        df3.setTimeZone(TimeZone.getTimeZone("GMT"));
        Date d = c.getTime();
        String s = d.toString();
        String ret = df.format(c.getTime());
        String ret2 = df.format(new Date(System.currentTimeMillis()));
        String ret3 = df2.format(c.getTime());
        String ret4 = df3.format(c.getTime());
        String r1 = ""+c.get(Calendar.HOUR);
        return ret;

I get the same results:

s = "Fri Jan 08 00:52:05 GMT 2016"
ret = "2016-01-08 01:52:05"
ret2 = "2016-01-08 01:52:05"
ret3 = "2016-01-08 24:52 GMT"
ret4 = "2016-01-08 01:52:05.169 GMT"
r1 = "0"

and

s = "Fri Jan 08 01:03:23 GMT 2016"
ret = "2016-01-08 01:03:23"
ret2 = "2016-01-08 01:03:23"
ret3 = "2016-01-08 01:03 GMT"
ret4 = "2016-01-08 01:03:23.547 GMT"
r1 = "1"

so the problem seems to be unrelated to TimeZone

Answer 1

May be you have to set the timeZone for your dateFormat objects.

I tried this :

    Calendar c = new GregorianCalendar(TimeZone.getTimeZone("GMT-11:00"), Locale.US);
    c.set(2016, 0, 7, 00, 39, 32);
    Date date  = c.getTime();

    SimpleDateFormat df = new SimpleDateFormat("EEE MMM dd HH:mm:ss zzz yyyy", Locale.US);
    df.setTimeZone(TimeZone.getTimeZone("GMT-11:00"));
    SimpleDateFormat df2 = new SimpleDateFormat("yyyy-MM-dd kk:mm", Locale.US);
    df2.setTimeZone(TimeZone.getTimeZone("GMT-11:00"));
    SimpleDateFormat df3 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS", Locale.US);
    df3.setTimeZone(TimeZone.getTimeZone("GMT-11:00"));

    String ret = df.format(date.getTime());
    String ret2 = df.format(date.getTime());
    String ret3 = df2.format(date.getTime());
    String ret4 = df3.format(date.getTime());

    System.out.println("  ret : "+ret);
    System.out.println("  ret2 : "+ret2);
    System.out.println("  ret3 kk: "+ret3);
    System.out.println("  ret4 : "+ret4);

The result is correct :

 ret : Thu Jan 07 00:39:32 GMT-11:00 2016
 ret2 : Thu Jan 07 00:39:32 GMT-11:00 2016
 ret3 kk: 2016-01-07 24:39
 ret4 : 2016-01-07 00:39:32.217

Answer 2

Idk... honestly. I tried recreting your problem, but in Eclipse on PC, not in Android. This is what I used:

    Calendar c = new GregorianCalendar(TimeZone.getTimeZone(ZoneId.ofOffset("", ZoneOffset.ofHours(-11))), Locale.US);
    c.set(2016, 0, 7, 0, 7);

    String strFormat = "yyyy-MM-dd HH:mm:ss.SSS";


    SimpleDateFormat df = new SimpleDateFormat(strFormat, Locale.US);
    SimpleDateFormat df2 = new SimpleDateFormat("yyyy-MM-dd kk:mm", Locale.US);
    SimpleDateFormat df3 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS", Locale.US);

    Date d = c.getTime();
    String s = d.toString();
    String ret = df.format(c.getTime());
    String ret2 = df.format(new Date(System.currentTimeMillis()));
    String ret3 = df2.format(c.getTime());
    String ret4 = df3.format(c.getTime());
    String r1 = ""+c.get(Calendar.HOUR);

    System.out.printf("s = %s%nret = %s%nret2 = %s%nret3 = %s%nret4 = %s%nr1 = %s%n%n", s, ret, ret2, ret3, ret4, r1);

    df.setTimeZone(TimeZone.getTimeZone(ZoneId.ofOffset("", ZoneOffset.ofHours(-11))));
    df2.setTimeZone(TimeZone.getTimeZone(ZoneId.ofOffset("", ZoneOffset.ofHours(-11))));
    df3.setTimeZone(TimeZone.getTimeZone(ZoneId.ofOffset("", ZoneOffset.ofHours(-11))));

    d = c.getTime();
    s = d.toString();
    ret = df.format(c.getTime());
    ret2 = df.format(new Date(System.currentTimeMillis()));
    ret3 = df2.format(c.getTime());
    ret4 = df3.format(c.getTime());
    r1 = ""+c.get(Calendar.HOUR);

    System.out.printf("s = %s%nret = %s%nret2 = %s%nret3 = %s%nret4 = %s%nr1 = %s%n%n", s, ret, ret2, ret3, ret4, r1);

    c.set(2016, 0, 7, 1, 7);

    d = c.getTime();
    s = d.toString();
    ret = df.format(c.getTime());
    ret2 = df.format(new Date(System.currentTimeMillis()));
    ret3 = df2.format(c.getTime());
    ret4 = df3.format(c.getTime());
    r1 = ""+c.get(Calendar.HOUR);

    System.out.printf("s = %s%nret = %s%nret2 = %s%nret3 = %s%nret4 = %s%nr1 = %s%n", s, ret, ret2, ret3, ret4, r1);

And this is what I got:

s = Thu Jan 07 12:07:58 CET 2016
ret = 2016-01-07 12:07:58.662
ret2 = 2016-01-07 17:55:58.697
ret3 = 2016-01-07 12:07
ret4 = 2016-01-07 12:07:58.662
r1 = 0

s = Thu Jan 07 12:07:58 CET 2016
ret = 2016-01-07 00:07:58.662
ret2 = 2016-01-07 05:55:58.718
ret3 = 2016-01-07 24:07
ret4 = 2016-01-07 00:07:58.662
r1 = 0

s = Thu Jan 07 13:07:58 CET 2016
ret = 2016-01-07 01:07:58.662
ret2 = 2016-01-07 05:55:58.722
ret3 = 2016-01-07 01:07
ret4 = 2016-01-07 01:07:58.662
r1 = 1

Maybe there is a problem in your SimpleDateFormat, which uses a different timezone... This is really interesting.