Java - unparseable date, need format to match “GMT-0400”

Question

I have the following Java:

DateFormat formatter = new SimpleDateFormat(
    \"EEE MMM dd yyyy HH:mm:ss zZ (zzzz)\", Locale.ENGLISH);
Calendar cal = Calendar.         


        

Answer 1

I debugged SimpleDateFormat and it seems that it will only parse GMT-04:00 but not GMT-0400.

It will accept UTC-0400, however it will throw away the hours/minutes modifier and will incorrectly parse it as UTC. (This happens with any other timezone designation, except for GMT)

It will also parse -0400 correctly, so the most robust solution is probably to simply remove GMT from your date string.

The upshot of the story is that SimpleDateFormat is anything but simple.

Update: Another lesson is that I could've saved a lot of time by passing a ParsePosition object to the parse() method:

    DateFormat formatter = new SimpleDateFormat(
        "EEE MMM dd yyyy HH:mm:ss zzzz", Locale.ENGLISH);
    Date date;
    ParsePosition pos = new ParsePosition( 0 );
    date = formatter
        .parse("Fri Apr 01 2011 00:00:00 UTC-0400", pos);
    System.out.println( pos.getIndex() );

Will print out 28, indicating that the parsing ended at character index 28, just after UTC.