We Keep Coding

Local Date to UTC conversion

I'm trying to convert system local date to UTC. Below is my code and it looks working for MST and EST formats. But, it is not working as expected.
String inputDate = "Wed Apr 13 04:00:00 IST 2022";
SimpleDateFormat sdf = new SimpleDateFormat("EEE MMM dd HH:mm:ss zzz yyyy");
Date date = sdf.parse(inputDate);
DateFormat formatUTC = new SimpleDateFormat("MM/dd/yyyy");
formatUTC.setTimeZone(TimeZone.getTimeZone("UTC"));
String result = formatUTC.format(date);
System.out.print(result); // 04/13/2022
I see that IST zone is 5hrs 30mins ahead from the UTC universal time. So, I should get 04/12/2022 for the given input. But, getting 04/13/2022. what am I doing wrong here? Please advise.

Try setting the timezone for inputDate as well. Try the below code:
String inputDate = "Wed Apr 13 04:00:00 IST 2022";
SimpleDateFormat sdf = new SimpleDateFormat("EEE MMM dd HH:mm:ss zzz yyyy");
sdf.setTimeZone(TimeZone.getTimeZone("Asia/Kolkata"));
Date date = sdf.parse(inputDate);
DateFormat formatUTC = new SimpleDateFormat("MM/dd/yyyy");
formatUTC.setTimeZone(TimeZone.getTimeZone("UTC"));
String result = formatUTC.format(date);
System.out.print(result);
Take a look at this answer.

Trouble parsing Java Date Object?

I am receiving a Java Date formatted like so: "Sun Sep 14 02:00:00 PDT 2014" into a yyyy-MM-dd format but I can't seem to parse it. What I tried is the following:
String time = "Sun Sep 14 02:00:00 PDT 2014";
SimpleDateFormat f = new SimpleDateFormat("yyyy-MM-dd");
Date contractEffectiveDateFormat = f.parse(time);
System.out.println("Date: " + contractEffectiveDateFormat);
However, I get an error saying that this date is unparsable. I'm not sure how to go about parsing this date because if I try to parse the date using the following:
DateFormat df = new SimpleDateFormat("EEE MMM dd kk:mm:ss z yyyy");
which is how to actually parse the date correctly into a Date object,
the string would turn into a Date object, but I can't seem to do anything with it from there. I want to turn it in so that it looks like 2014-09-14. Any ideas on how to do so? Thanks!

Use two DateFormat(s) one for input and for output,
String time = "Sun Sep 14 02:00:00 PDT 2014";
DateFormat out = new SimpleDateFormat("yyyy-MM-dd");
DateFormat in = new SimpleDateFormat("EEE MMM dd kk:mm:ss z yyyy");
try {
Date effectiveDate = in.parse(time);
System.out.println("Date: " + out.format(effectiveDate));
} catch (ParseException e) {
e.printStackTrace();
}
Output is the requested
Date: 2014-09-14

Your incoming string is this String time = "Sun Sep 14 02:00:00 PDT 2014";
which means the SimpleDateFormat pattern should match the incoming String pattern so you need to use SimpleDateFormat like this
DateFormat inFormat=new SimpleDateFormat("EEE MMM dd kk:mm:ss z yyyy",Locale.ENGLISH);
Then when you called parse() on inFormat it will give you Date Object which doesnot have particular format associated with it. So in order to format the Date again you need to create SimpleDateFormat object specifying the format you want which is this
DateFormat outFormat = new SimpleDateFormat("yyyy-MM-dd", Locale.ENGLISH);
Ultimately bind all together
One more thing always specify the Locale
String time = "Sun Sep 14 02:00:00 PDT 2014";
DateFormat outFormat = new SimpleDateFormat("yyyy-MM-dd", Locale.ENGLISH);
// good practice to specify the locale
DateFormat inFormat=new SimpleDateFormat("EEE MMM dd kk:mm:ss z yyyy",Locale.ENGLISH);
try {
Date parsedDate = inFormat.parse(time);
System.out.println("Required Formatted Date: " + outFormat.format(effectiveDate));
} catch (ParseException e) {
e.printStackTrace();
}

Simply add another SimpleDateFormat that'll allow you to present the Date object the way you want:
public static void main(String[] args) throws ParseException {
String time = "Sun Sep 14 02:00:00 PDT 2014";
DateFormat df = new SimpleDateFormat("EEE MMM dd kk:mm:ss z yyyy");
Date contractEffectiveDateFormat = df.parse(time);
System.out.println("Date: " + contractEffectiveDateFormat);
SimpleDateFormat f = new SimpleDateFormat("yyyy-MM-dd");
System.out.println(f.format(contractEffectiveDateFormat)); // prints 2014-09-14
}

How can I convert a String to a Date and then to a different format?

Actually I wanted to convert one String to date and then I need to format it in to one another format..
The String I have is
String val="Wed Jan 08 08:49:13 GMT+05:30 2014";
To convert it to
2014-01-30 10:14:18 , this format
Is it possible to do this I tried some method like
SimpleDateFormat df = new SimpleDateFormat("dd-MMM-yyyy");
String formattedDate = df.format(c.getTime());
Calendar cal = Calendar.getInstance(TimeZone.getTimeZone("GMT+1:00"));
// Date currentLocalTime = ;
DateFormat date = new SimpleDateFormat("HH:mm:ss:mmss a");
But nothing worked

Your format string for parsing doesn't match the example date you have given.
You could try something like the following:
String val = "Wed Jan 08 08:49:13 GMT+05:30 2014";
DateFormat inFmt = new SimpleDateFormat("EEE MMM dd HH:mm:ss Z yyyy");
Date date = inFmt.parse(val);
DateFormat outFmt = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
outFmt.setTimeZone(TimeZone.getTimeZone("GMT+1:00"));
System.out.println(outFmt.format(date));
Note the following correspondences in the first two lines:
Wed -> EEE
Jan -> MMM
08 -> dd
etc.

Parsing Date from Formatted String in Java

I have a string with format "Mon Dec 03 00:00:00 IST 2012". I want to convert this string into Date. Any formats will do.

can try:
SimpleDateFormat sdf = new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy");
try {
Date date = sdf.parse("Mon Dec 03 00:00:00 IST 2012");
} catch (ParseException e) {
e.printStackTrace();
}

You can use parse() method of SimpleDateFormat class. Read the API documentation here.

date format of your string-represented date is:
DateFormat df = new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy");

Use a SimpleDateFormatter. You can find details about them here:
SimpleDateFormat

DateFormat dateFormat = new SimpleDateFormat("E MMM dd HH:mm:ss zzz yyyy");

How to handle the Time data from the Style just like "Wed Jun 20 11:01:05 +0800 2012"?

In my project ,I get json data from Server,there's a field named 'creat_at' in the json which style is like 'Wed Jun 20 11:01:05 +0800 2012'
How to change it to more easy-to-read style like '2012/06/20'?
(I have tried 'DateFormat.parse' but it dose not work:
new SimpleDateFormat("EEE MMM dd HH:mm:ss Z yyyy").parse(dateString)
cause
java.text.ParseException: Unparseable date: "Wed Jun 20 11:00:53 +0800 2012")

See SimpleDateFormat API
Date date = new SimpleDateFormat("EEE MMM dd HH:mm:ss Z yyyy").parse(dateString);
String formattedDate = new SimpleDateFormat("yyyy/MM/dd").format(date);

You need to try SimpleDateFormat
SimpleDateFormat sdf = new SimpleDateFormat("EEE MMM dd HH:mm:ss Z yyyy");
SimpleDateFormat sdf2 = new SimpleDateFormat("yyyy/MM/dd");
System.out.println(sdf2.format(sdf.parse("Wed Jun 20 11:01:05 +0800 2012")));
prints
2012/06/20
You may also need to set an approriate timezone.