What Are the Date Formats Available in Simpledateformat Class

What are the date formats available in SimpleDateFormat class?

Date and time formats are well described below

SimpleDateFormat (Java Platform SE 7) - Date and Time Patterns

There could be n Number of formats you can possibly make. ex - dd/MM/yyyy or YYYY-'W'ww-u or you can mix and match the letters to achieve your required pattern. Pattern letters are as follow.

G - Era designator (AD)
y - Year (1996; 96)
Y - Week Year (2009; 09)
M - Month in year (July; Jul; 07)
w - Week in year (27)
W - Week in month (2)
D - Day in year (189)
d - Day in month (10)
F - Day of week in month (2)
E - Day name in week (Tuesday; Tue)
u - Day number of week (1 = Monday, ..., 7 = Sunday)
a - AM/PM marker
H - Hour in day (0-23)
k - Hour in day (1-24)
K - Hour in am/pm (0-11)
h - Hour in am/pm (1-12)
m - Minute in hour (30)
s - Second in minute (55)
S - Millisecond (978)
z - General time zone (Pacific Standard Time; PST; GMT-08:00)
Z - RFC 822 time zone (-0800)
X - ISO 8601 time zone (-08; -0800; -08:00)

To parse:

2000-01-23T04:56:07.000+0000

Use:
new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSZ");

What is this date format? 2011-08-12T20:17:46.384Z

The T is just a literal to separate the date from the time, and the Z means "zero hour offset" also known as "Zulu time" (UTC). If your strings always have a "Z" you can use:

SimpleDateFormat format = new SimpleDateFormat(
    "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'", Locale.US);
format.setTimeZone(TimeZone.getTimeZone("UTC"));

Or using Joda Time, you can use ISODateTimeFormat.dateTime().

What is the date format of 2019-06-17T20:27:23.706000000Z?

Try this:

import java.text.SimpleDateFormat;
import java.util.Date;
import java.text.DateFormat;
import java.util.TimeZone;

public class Main
{
    public static void main(String[] args){
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS");
        try{
            Date date = sdf.parse("2019-06-17T20:27:23.706Z");
            System.out.println(date);
        }
        catch(Exception pe){
            System.out.println(pe);
        }

    }
}

output:

Mon Jun 17 20:27:23 UTC 2019

By the way, you can also try this:

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSSSSSSS'Z'");

Both gives the same result

Try using Instant from java.time package(java 8).

String value = "2019-06-17T20:27:23.706000000Z";
Instant instant = Instant.parse(value);
Date date = Date.from(instant);

Java SimpleDateFormat(yyyy-MM-dd'T'HH:mm:ss'Z') gives timezone as IST

You haven't set the timezone only added a Z to the end of the date/time, so it will look like a GMT date/time but this doesn't change the value.

Set the timezone to GMT and it will be correct.

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
sdf.setTimeZone(TimeZone.getTimeZone("GMT"));

Different Date Formats

I should like to challenge what you are asking for. Of course you can have it, as your own answer already shows. But do you want it?

Use the built-in localized formats

Java has localized formats for all available locales (I think it’s all, in any case it’s many). I suggest you use these rather than your own idea of what a localized date should look like. While 28.Okt.2015 is probably commonplace in Austria and other German-speaking places, English-speaking people are not used to the dots in your format, and I would suspect that some people in the world will find it more or less strange.

I suggested in a comment that you add ThreeTenABP to your Android project in order to use java.time, the modern Java date and time API. It is so much nicer to work with. Now I am taking my own medicine:

    DateTimeFormatter dateFormatter = DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM);
    LocalDate myDate = LocalDate.of(2015, Month.OCTOBER, 28);
    System.out.println(myDate.format(dateFormatter));

Output in different locales include:

German:     28.10.2015
UK English: 28 Oct 2015
French:     28 oct. 2015

It’s not what you asked for. And you may meet objections, but that will happen no matter which format you choose because many people have their own ideas about the proper formatting for their locale. It’s pretty standardized, though, so consider it.

Edit: where did the LocalDate come from?

I understood that you were converting from a string like "28.10.2015". Converting this to a LocalDate is straightforward when you know how:

    DateTimeFormatter numericDateFormatter = DateTimeFormatter.ofPattern("dd.MM.uuuu");
    LocalDate myDate = LocalDate.parse("28.10.2015", numericDateFormatter);

Only if you got a java.util.Date from a legacy API that you cannot change or do not want to change just now, first thing convert it to the modern Instant type and do further conversions from there:

    LocalDate myDate = oldfashionedJavaUtilDate.toInstant()
            .atZone(ZoneId.of("Europe/Vienna"))
            .toLocalDate();

Since this is a time zone sensitive operation, I recommend you specify an explicit time zone. You may use the JVM’s time zone setting by specifying ZoneId.systemDefault(), but be aware that this is fragile: the JVM setting may be changed under your feet by other parts of your program or other programs running in the same JVM.

What you asked for

The java.time edition of what you asked for is pretty similar to the code in your own answer:

    DateTimeFormatter dateFormatter = DateTimeFormatter.ofPattern("dd");
    DateTimeFormatter monthFormatter = DateTimeFormatter.ofPattern("MMMM");
    DateTimeFormatter yearFormatter = DateTimeFormatter.ofPattern("uuuu");
    LocalDate myDate = LocalDate.of(2015, Month.OCTOBER, 28);
    String dayOfMonth = myDate.format(dateFormatter);
    String monthName = myDate.format(monthFormatter);
    if (monthName.length() > 3) {
        monthName = monthName.substring(0, 3);
    }
    String year = myDate.format(yearFormatter);
    String formattedDate = dayOfMonth + '.' + monthName + '.' + year;
    System.out.println(formattedDate);

Output in the same locales as above:

German:     28.Okt.2015
UK English: 28.Oct.2015
French:     28.oct.2015

There is a much shorter way to obtain the same, though:

    String formattedDate = String.format("%1$td.%2$.3s.%1$tY", 
            myDate,
            myDate.getMonth().getDisplayName(TextStyle.FULL, Locale.getDefault()));

It’s harder to read. It took me a number of attempts to get the format string %1$td.%2$.3s.%1$tY exactly right. And it will surprise those maintaining your code if they are used to DateTimeFormatter for formatting dates (and times). So I don’t really recommend it, but the choice is yours.

With another date I got the following output in French locale:

08.jui.2018

No French-speaking person, nor anyone else for that matter, will know whether this date was in June (juin) or July (juillet). In 57 of the available locales in my JVM, all 12 months of the year begin with the same three letters. Such locales include Tibetan, Swahili, Somali, Cornish, Scottish Gaelic and Vietnamese. In these languages nobody will be able to tell any months apart. Please think twice.

SimpleDateFormat and locale based format string

Use DateFormat.getDateInstance(int style, Locale locale) instead of creating your own patterns with SimpleDateFormat.

java.util.Date format conversion yyyy-mm-dd to mm-dd-yyyy

Date is a container for the number of milliseconds since the Unix epoch ( 00:00:00 UTC on 1 January 1970).

It has no concept of format.

Java 8+

LocalDateTime ldt = LocalDateTime.now();
System.out.println(DateTimeFormatter.ofPattern("MM-dd-yyyy", Locale.ENGLISH).format(ldt));
System.out.println(DateTimeFormatter.ofPattern("yyyy-MM-dd", Locale.ENGLISH).format(ldt));
System.out.println(ldt);

Outputs...

05-11-2018
2018-05-11
2018-05-11T17:24:42.980

Java 7-

You should be making use of the ThreeTen Backport

Original Answer

For example...

Date myDate = new Date();
System.out.println(myDate);
System.out.println(new SimpleDateFormat("MM-dd-yyyy").format(myDate));
System.out.println(new SimpleDateFormat("yyyy-MM-dd").format(myDate));
System.out.println(myDate);

Outputs...

Wed Aug 28 16:20:39 EST 2013
08-28-2013
2013-08-28
Wed Aug 28 16:20:39 EST 2013

None of the formatting has changed the underlying Date value. This is the purpose of the DateFormatters

Updated with additional example

Just in case the first example didn't make sense...

This example uses two formatters to format the same date. I then use these same formatters to parse the String values back to Dates. The resulting parse does not alter the way Date reports it's value.

Date#toString is just a dump of it's contents. You can't change this, but you can format the Date object any way you like

try {
    Date myDate = new Date();
    System.out.println(myDate);

    SimpleDateFormat mdyFormat = new SimpleDateFormat("MM-dd-yyyy");
    SimpleDateFormat dmyFormat = new SimpleDateFormat("yyyy-MM-dd");

    // Format the date to Strings
    String mdy = mdyFormat.format(myDate);
    String dmy = dmyFormat.format(myDate);

    // Results...
    System.out.println(mdy);
    System.out.println(dmy);
    // Parse the Strings back to dates
    // Note, the formats don't "stick" with the Date value
    System.out.println(mdyFormat.parse(mdy));
    System.out.println(dmyFormat.parse(dmy));
} catch (ParseException exp) {
    exp.printStackTrace();
}

Which outputs...

Wed Aug 28 16:24:54 EST 2013
08-28-2013
2013-08-28
Wed Aug 28 00:00:00 EST 2013
Wed Aug 28 00:00:00 EST 2013

Also, be careful of the format patterns. Take a closer look at SimpleDateFormat to make sure you're not using the wrong patterns ;)

What Are the Date Formats Available in Simpledateformat Class