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my Date Util formatter does not return my intended date format need help, [duplicate]

How to convert calendar date to yyyy-MM-dd format.
Calendar cal = Calendar.getInstance();
cal.add(Calendar.DATE, 1);
Date date = cal.getTime();
SimpleDateFormat format1 = new SimpleDateFormat("yyyy-MM-dd");
String date1 = format1.format(date);
Date inActiveDate = null;
try {
inActiveDate = format1.parse(date1);
} catch (ParseException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
This will produce inActiveDate = Wed Sep 26 00:00:00 IST 2012. But what I need is 2012-09-26. My purpose is to compare this date with another date in my database using Hibernate criteria. So I need the date object in yyyy-MM-dd format.

A Java Date is a container for the number of milliseconds since January 1, 1970, 00:00:00 GMT.
When you use something like System.out.println(date), Java uses Date.toString() to print the contents.
The only way to change it is to override Date and provide your own implementation of Date.toString(). Now before you fire up your IDE and try this, I wouldn't; it will only complicate matters. You are better off formatting the date to the format you want to use (or display).
Java 8+
LocalDateTime ldt = LocalDateTime.now().plusDays(1);
DateTimeFormatter formmat1 = DateTimeFormatter.ofPattern("yyyy-MM-dd", Locale.ENGLISH);
System.out.println(ldt);
// Output "2018-05-12T17:21:53.658"
String formatter = formmat1.format(ldt);
System.out.println(formatter);
// 2018-05-12
Prior to Java 8
You should be making use of the ThreeTen Backport
The following is maintained for historical purposes (as the original answer)
What you can do, is format the date.
Calendar cal = Calendar.getInstance();
cal.add(Calendar.DATE, 1);
SimpleDateFormat format1 = new SimpleDateFormat("yyyy-MM-dd");
System.out.println(cal.getTime());
// Output "Wed Sep 26 14:23:28 EST 2012"
String formatted = format1.format(cal.getTime());
System.out.println(formatted);
// Output "2012-09-26"
System.out.println(format1.parse(formatted));
// Output "Wed Sep 26 00:00:00 EST 2012"
These are actually the same date, represented differently.

Your code is wrong. No point of parsing date and keep that as Date object.
You can format the calender date object when you want to display and keep that as a string.
Calendar cal = Calendar.getInstance();
cal.add(Calendar.DATE, 1);
Date date = cal.getTime();
SimpleDateFormat format1 = new SimpleDateFormat("yyyy-MM-dd");
String inActiveDate = null;
try {
inActiveDate = format1.format(date);
System.out.println(inActiveDate );
} catch (ParseException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}

java.time
The answer by MadProgrammer is correct, especially the tip about Joda-Time. The successor to Joda-Time is now built into Java 8 as the new java.time package. Here's example code in Java 8.
When working with date-time (as opposed to local date), the time zone in critical. The day-of-month depends on the time zone. For example, the India time zone is +05:30 (five and a half hours ahead of UTC), while France is only one hour ahead. So a moment in a new day in India has one date while the same moment in France has “yesterday’s” date. Creating string output lacking any time zone or offset information is creating ambiguity. You asked for YYYY-MM-DD output so I provided, but I don't recommend it. Instead of ISO_LOCAL_DATE I would have used ISO_DATE to get this output: 2014-02-25+05:30
ZoneId zoneId = ZoneId.of( "Asia/Kolkata" );
ZonedDateTime zonedDateTime = ZonedDateTime.now( zoneId );
DateTimeFormatter formatterOutput = DateTimeFormatter.ISO_LOCAL_DATE; // Caution: The "LOCAL" part means we are losing time zone information, creating ambiguity.
String output = formatterOutput.format( zonedDateTime );
Dump to console…
System.out.println( "zonedDateTime: " + zonedDateTime );
System.out.println( "output: " + output );
When run…
zonedDateTime: 2014-02-25T14:22:20.919+05:30[Asia/Kolkata]
output: 2014-02-25
Joda-Time
Similar code using the Joda-Time library, the precursor to java.time.
DateTimeZone zone = new DateTimeZone( "Asia/Kolkata" );
DateTime dateTime = DateTime.now( zone );
DateTimeFormatter formatter = ISODateTimeFormat.date();
String output = formatter.print( dateTime );
ISO 8601
By the way, that format of your input string is a standard format, one of several handy date-time string formats defined by ISO 8601.
Both Joda-Time and java.time use ISO 8601 formats by default when parsing and generating string representations of various date-time values.

java.util.Date object can't represent date in custom format instead you've to use SimpleDateFormat.format method that returns string.
String myString=format1.format(date);

public static void main(String[] args) {
Calendar cal = Calendar.getInstance();
cal.set(year, month, date);
SimpleDateFormat format1 = new SimpleDateFormat("yyyy MM dd");
String formatted = format1.format(cal.getTime());
System.out.println(formatted);
}

In order to parse a java.util.Date object you have to convert it to String first using your own format.
inActiveDate = format1.parse( format1.format(date) );
But I believe you are being redundant here.

Calendar cal = Calendar.getInstance();
cal.add(Calendar.DATE, 7);
Date date = c.getTime();
SimpleDateFormat ft = new SimpleDateFormat("MM-dd-YYYY");
JOptionPane.showMessageDialog(null, ft.format(date));
This will display your date + 7 days in month, day and year format in a JOption window pane.

public static String ThisWeekStartDate(WebDriver driver) {
Calendar c = Calendar.getInstance();
//ensure the method works within current month
c.set(Calendar.DAY_OF_WEEK, Calendar.SUNDAY);
System.out.println("Before Start Date " + c.getTime());
Date date = c.getTime();
SimpleDateFormat dfDate = new SimpleDateFormat("dd MMM yyyy hh.mm a");
String CurrentDate = dfDate.format(date);
System.out.println("Start Date " + CurrentDate);
return CurrentDate;
}
public static String ThisWeekEndDate(WebDriver driver) {
Calendar c = Calendar.getInstance();
//ensure the method works within current month
c.set(Calendar.DAY_OF_WEEK, Calendar.SATURDAY);
System.out.println("Before End Date " + c.getTime());
Date date = c.getTime();
SimpleDateFormat dfDate = new SimpleDateFormat("dd MMM yyyy hh.mm a");
String CurrentDate = dfDate.format(date);
System.out.println("End Date " + CurrentDate);
return CurrentDate;
}

I found this code where date is compared in a format to compare with date field in database...may be this might be helpful to you...
When you convert the string to date using simpledateformat, it is hard to compare with the Date field in mysql databases.
So convert the java string date in the format using select STR_to_DATE('yourdate','%m/%d/%Y') --> in this format, then you will get the exact date format of mysql date field.
http://javainfinite.com/java/java-convert-string-to-date-and-compare/

My answer is for kotlin language.
You can use SimpleDateFormat to achieve the result:
val date = Date(timeInSec)
val formattedDate = SimpleDateFormat("yyyy-MM-dd", Locale("IN")).format(date)
for details click here.
OR
Use Calendar to do it for you:
val dateObject = Date(timeInMillis)
val calendarInstance = Calendar.getInstance()
calendarInstance.time = dateObject
val date = "${calendarInstance.get(Calendar.YEAR)}-${calendarInstance.get(Calendar.MONTH)}-${calendarInstance.get(Calendar.DATE)}"
For more details check this answer.

I don't know about y'all, but I always want this stuff as a one-liner. The other answers are fine and dandy and work great, but here is it condensed to a single line. Now you can hold less lines of code in your mind :-).
Here is the one Liner:
String currentDate = new SimpleDateFormat("yyyy-MM-dd").format(new Date());

how to get dateTime based on hour and minute

I have hour and minute in edittext.(say for example 10:50)
how to get today's DateTime(like yyyy-MM-dd HH:mm:ss) based on above edit text value 10:50
UPDATE:
this worked for me:
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR, selectedHour);
calendar.set(Calendar.MINUTE, selectedMinute);
thank you all

EDIT: take a look at this other stackoverflow post about why one should prefer using the Java 8 java.time classes over Calendar or Date
In your instance, in order to parse an input in the form "HH:mm", you can create a DateTimeFormatter and use the static method LocalTime.parse(inputString, dateTimeFormatter) to get a LocalTime object
For example:
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("HH:mm");
LocalTime time = LocalTime.parse(timeInputString, formatter);
Take a look at the Java documentation for DateTimeFormatter for more information on the patterns for years, days, or whatever.
If you're wanting to get both the date and time from a string such as "10:50", you won't be able to using the LocalDateTime.parse method because it can't obtain the date from an "HH:mm" string. So the way around this is to create the time off of LocalTime.parse as shown above, and then get the current date using the static method LocalDate.now(); And then combine those two results into a LocalDateTime object using it's static factory method LocalDateTime.of(date, time)
For example:
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("HH:mm");
LocalTime time = LocalTime.parse(timeInputString, formatter);
LocalDate date = LocalDate.now();
LocalDateTime dateTime = LocalDateTime.of(date, time);

Calendar cal = new Calendar.getInstance();// today's date
cal.set(Calendar.HOUR, 10);
cal.set(Calendar.MINUTE, 50);
cal.set(Calendar.SECOND, 0);
System.out.println(cal.getTime()); //see the result
now , it's up to you to put them directly in cal.set with variables (not manually writing 10 ,50 , it's up to your creativity )
And this answer is with Calendar because you tagged Calendar in your question , you can also use something else than Calender

you just need use this function.
// hourMintText = "hh:mm"
private String getTodayAsFormat(String hourMintText){
String[] hourMinAsArray = hourMintText.split(":");
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY, Integer.parseInt(hourMinAsArray[0]));
calendar.set(Calendar.MINUTE, Integer.parseInt(hourMinAsArray[1]));
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-mm-dd hh:mm", Locale.ENGLISH);
return simpleDateFormat.format(calendar.getTimeInMillis());
}

Try this:
String dateTime = new SimpleDateFormat("dd-MM-yyyy hh-mm-ss aa", Locale.getDefault())
.format(new Date());

how to compare two calendar objects?

I want to compare two date objects like this:
String format = "MM/dd/yyyy hh:mm a";
SimpleDateFormat sdf = new SimpleDateFormat(format);
fakeDate = sdf.parse("15/07/2013 11:00 AM");
fakeDate2 = sdf.parse("15/07/2013 12:00 AM");
int diff = date2.getHours() - date1.getHours();
but then I see getHours is deprecated.
So i have used:
Calendar calendar1 = Calendar.getInstance();
calendar.setTime(new Date("15/7/2013 11:00AM"));
Calendar calendar2 = Calendar.getInstance();
calendar.setTime(new Date("11/7/2013 12:00AM"));
calendar1.get(Calendar.HOUR_OF_DAY) - calendar2.get(Calendar.HOUR_OF_DAY)
but then I see the diff is zero. I guess i change the same calendar instance all the time and compare it to itself. no?
how would you write this?

new Date("15/7/2013 11:00AM")
is not the correct way to construct a Date object. It's deprecated also. Use proper SimpleDateFormat as you are doing well in your first example.
The format MM/dd/yyyy hh:mm a is not correct as per the input date string.
It should be like this.
String format = "dd/MM/yyyy hh:mm a";
SimpleDateFormat sdf = new SimpleDateFormat(format);
Date fakeDate = sdf.parse("15/07/2013 11:00 AM");
Date fakeDate2 = sdf.parse("15/07/2013 12:00 AM");
Calendar cal = Calendar.getInstance();
cal.setTime(fakeDate); //set time to first date
int hours1 = cal.get(Calendar.HOUR); // get the hours
cal.setTime(fakeDate2); // set time to second date
int hours2 = cal.get(Calendar.HOUR); // get the hours
System.out.println(hours1 - hours2); // 11 hours

You seemed really confused though it is depreciated this code shall give you a difference of 11 hours which makes sense
SimpleDateFormat dateFormat = new SimpleDateFormat("MM/dd/yyyy hh:mm a");
Date fakeDate = dateFormat.parse("15/07/2013 11:00 AM");
Date fakeDate2 = dateFormat.parse("15/07/2013 12:00 AM");
System.out.println(fakeDate.getHours()-fakeDate2.getHours());
Or if you are so interested to use Calendar do it this way
Calendar calendar = Calendar.getInstance();
calendar.setTime(fakeDate);
Calendar calendar2 = Calendar.getInstance();
calendar2.setTime(fakeDate2);
System.out.println(calendar.get(Calendar.HOUR_OF_DAY) -
calendar2.get(Calendar.HOUR_OF_DAY));
You will get the same 11 hours difference or simply do it this way
long millisForNewDate = toDate.getTime();
long millisForOldDate = fromDate.getTime();
long difference = millisForNewDate - millisForOldDate;
int hoursDifferenceBetweenDates = (int)(difference/(1000*60*60));

How to subtract X day from a Date object in Java?

I want to do something like:
Date date = new Date(); // current date
date = date - 300; // substract 300 days from current date and I want to use this "date"
How to do it?

Java 8 and later
With Java 8's date time API change, Use LocalDate
LocalDate date = LocalDate.now().minusDays(300);
Similarly you can have
LocalDate date = someLocalDateInstance.minusDays(300);
Refer to https://stackoverflow.com/a/23885950/260990 for translation between java.util.Date <--> java.time.LocalDateTime
Date in = new Date();
LocalDateTime ldt = LocalDateTime.ofInstant(in.toInstant(), ZoneId.systemDefault());
Date out = Date.from(ldt.atZone(ZoneId.systemDefault()).toInstant());
Java 7 and earlier
Use Calendar's add() method
Calendar cal = Calendar.getInstance();
cal.setTime(dateInstance);
cal.add(Calendar.DATE, -30);
Date dateBefore30Days = cal.getTime();

#JigarJoshi it's the good answer, and of course also #Tim recommendation to use .joda-time.
I only want to add more possibilities to subtract days from a java.util.Date.
Apache-commons
One possibility is to use apache-commons-lang. You can do it using DateUtils as follows:
Date dateBefore30Days = DateUtils.addDays(new Date(),-30);
Of course add the commons-lang dependency to do only date subtract it's probably not a good options, however if you're already using commons-lang it's a good choice. There is also convenient methods to addYears,addMonths,addWeeks and so on, take a look at the api here.
Java 8
Another possibility is to take advantage of new LocalDate from Java 8 using minusDays(long days) method:
LocalDate dateBefore30Days = LocalDate.now(ZoneId.of("Europe/Paris")).minusDays(30);

Simply use this to get date before 300 days, replace 300 with your days:
Date date = new Date(); // Or where ever you get it from
Date daysAgo = new DateTime(date).minusDays(300).toDate();
Here,
DateTime is org.joda.time.DateTime;
Date is java.util.Date

Java 8 Time API:
Instant now = Instant.now(); //current date
Instant before = now.minus(Duration.ofDays(300));
Date dateBefore = Date.from(before);

As you can see HERE there is a lot of manipulation you can do. Here an example showing what you could do!
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Calendar cal = Calendar.getInstance();
//Add one day to current date.
cal.add(Calendar.DATE, 1);
System.out.println(dateFormat.format(cal.getTime()));
//Substract one day to current date.
cal = Calendar.getInstance();
cal.add(Calendar.DATE, -1);
System.out.println(dateFormat.format(cal.getTime()));
/* Can be Calendar.DATE or
* Calendar.MONTH, Calendar.YEAR, Calendar.HOUR, Calendar.SECOND
*/

With Java 8 it's really simple now:
LocalDate date = LocalDate.now().minusDays(300);
A great guide to the new api can be found here.

In Java 8 you can do this:
Instant inst = Instant.parse("2018-12-30T19:34:50.63Z");
// subtract 10 Days to Instant
Instant value = inst.minus(Period.ofDays(10));
// print result
System.out.println("Instant after subtracting Days: " + value);

I have created a function to make the task easier.
For 7 days after dateString: dateCalculate(dateString,"yyyy-MM-dd",7);
To get 7 days upto dateString: dateCalculate(dateString,"yyyy-MM-dd",-7);
public static String dateCalculate(String dateString, String dateFormat, int days) {
Calendar cal = Calendar.getInstance();
SimpleDateFormat s = new SimpleDateFormat(dateFormat);
try {
cal.setTime(s.parse(dateString));
} catch (ParseException e) {
e.printStackTrace();
}
cal.add(Calendar.DATE, days);
return s.format(cal.getTime());
}

You may also be able to use the Duration class. E.g.
Date currentDate = new Date();
Date oneDayFromCurrentDate = new Date(currentDate.getTime() - Duration.ofDays(1).toMillis());

You can easily subtract with calendar with SimpleDateFormat
public static String subtractDate(String time,int subtractDay) throws ParseException {
Calendar cal = Calendar.getInstance();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm", Locale.ENGLISH);
cal.setTime(sdf.parse(time));
cal.add(Calendar.DATE,-subtractDay);
String wantedDate = sdf.format(cal.getTime());
Log.d("tag",wantedDate);
return wantedDate;
}

Java ResultSet how to getTimeStamp in UTC

The database has data in UTC and when I try to get data
java.util.Calendar cal = Calendar.getInstance();
cal.setTimeZone(TimeZone.getTimeZone("UTC"));
java.sql.Timestamp ts = resultSet.getTimestamp(PUBLISH_TIME);
cal.setTime(ts);
Is there anything wrong with this?

java.util.Calendar cal = Calendar.getInstance();
cal.setTimeZone(TimeZone.getTimeZone("UTC"));
java.sql.Timestamp ts = resultSet.getTimestamp(PUBLISH_TIME, cal);
This should do the trick!

Your DateFormat instance is most likely displaying the value in local time. When displaying your value, give this a try:
java.util.Calendar cal = Calendar.getInstance();
cal.setTimeZone(TimeZone.getTimeZone("UTC"));
java.sql.Timestamp ts = resultSet.getTimestamp(PUBLISH_TIME);
cal.setTime(ts);
SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss z");
sdf.setTimeZone(TimeZone.getTimeZone("UTC"));
System.out.println(sdf.format(cal.getTime()));
EDIT: to your comment:
What if I use GMT, would that be an issue in SimpleDateFormat
SimpleDateFormat can use general timezones (GMT +/- n), RFC822, and text ("if they have names" as the JavaDoc states - see this post for info on the names).