Develop Reference

Date in String to Date in Date conversion

I'm having date in String format as "2019-10-30 12:17:47". I want to convert this to an instance of Date along with the time so that I can compare two date obejcts.
This is what I've tried:
String dateString = "2019-10-30 12:17:47" //Date in String format
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH-mm-ss"); //sdf
Date d1 = format.parse(dateString);
But here I'm getting exception as "Unparseble date exception".
Kindly help...

What went wrong in your code?
In your format pattern string, yyyy-MM-dd HH-mm-ss, you have got two spaces between the date and the time. Since your date string, 2019-10-30 12:17:47, has got only one space there, your formatter objects by throwing the exception. This was also what Tim Biegeleisen said in a comment. The comment by deHaar is true too: The hyphens between hour, minute and second don’t match the colons in your date string either.
What to do instead?
See the good answer by deHaar

You should really switch to java.time (as already suggested in one of the comments below your question). It isn't more difficult than the outdated temporal classes from java.util but less error-prone and more powerful concerning offsets, time zones, daylight saving time and the multitude of different calendars the world has.
See this little example:
public static void main(String[] args) {
String dateString = "2019-10-30 12:17:47";
// define your pattern, should match the one of the String ;-)
String datePattern = "yyyy-MM-dd HH:mm:ss";
// parse the datetime using the pattern
LocalDateTime ldt = LocalDateTime.parse(dateString,
DateTimeFormatter.ofPattern(datePattern));
// print it using a different (here a built-in) formatting pattern
System.out.println(ldt.format(DateTimeFormatter.ISO_LOCAL_DATE_TIME));
// or you just use the one defined by you
System.out.println(ldt.format(DateTimeFormatter.ofPattern(datePattern)));
// or you define another one for the output
System.out.println(ldt.format(DateTimeFormatter.ofPattern("MMM dd yyyy HH-mm-ss")));
}
The output on my system looks like this:
2019-10-30T12:17:47
2019-10-30 12:17:47
Okt 30 2019 12-17-47

The date in string you want to format does not match the formatter. See more detail here,
https://docs.oracle.com/javase/tutorial/i18n/format/simpleDateFormat.html
#Test
public void test2() {
String dateString = "2019-10-30 12:17:47"; //Date in String format
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); //sdf
try {
Date d1 = format.parse(dateString);
} catch (ParseException e) {
e.printStackTrace();
}
}

There are two ways to do it
first is your way
String dateString = "2019-10-30 12:17:47"; // Date in String format
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); // sdf
Date d1 = format.parse(dateString
second is my way (Local date)
LocalDate resultDate = dateFormat("2019-10-30 12:17:47");
System.out.println(resultDate);
public static LocalDate dateFormat(String textTypeDateTime) {
final DateTimeFormatter dateTimetextFormatter =
DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
return LocalDate.parse(textTypeDateTime, dateTimetextFormatter);
}

Formatting TimeZoneDesignator

Need to format this String 2017-08-01T15:43:45+0530 to 2017-08-01T15:43:45+05:30 using a particular date format. Tried with yyyy-MM-dd'T'HH:mm:ssZZ. Did not work..
Date modified = aemPage.getProperties().get(cq:lastModified, Date.class);
private DateFormat seoDateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZZ");
String formattedDate = seoDateFormat.format(modified));

You need three X to get off set like
Sign TwoDigitHours : Minutes
I suggest to use OffsetDateTime if you are working with java8 or higher:
String input = "2017-08-01T15:43:45+0530";
DateTimeFormatter parser = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ssZ");
OffsetDateTime offsetDateTime = OffsetDateTime.parse(input, parser);
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ssXXX");
System.out.println(offsetDateTime.format(formatter)); // 2017-08-01T15:43:45+05:30
Since 2017-08-01T15:43:45+05:30 is ISO_OFFSET_DATE_TIME, you can also just use:
String outPut = offsetDateTime.toString();
Update:
If you want to use SimpleDateFormat, try:
String input = "2017-08-01T15:43:45+0530";
SimpleDateFormat parser = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ");
Date date = parser.parse(input);
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssXXX");
System.out.println(formatter.format(date));
But this only works when your system's offset is 0530 since Date does not hold time zone information.

Java - SimpleDateFormat parse from String issue

I'm trying to parse the following string to a Date object:
String str = "04/15/2014 10:30:24"
I'm using SimpleDateFormat :
SimpleDateFormat sdf = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss");
java.util.Date orderDate = sdf.parse(str);
java.sql.Date orderSqlDate = new java.sql.Date(orderDate.getTime());
but orderSqlDate always returned: 04/15/2014 00:00:00
how to use SimpleDateFormat in java exactly?

The java.sql.Date javadoc states
To conform with the definition of SQL DATE, the millisecond values
wrapped by a java.sql.Date instance must be 'normalized' by setting
the hours, minutes, seconds, and milliseconds to zero in the
particular time zone with which the instance is associated.
If you're going to use java.sql.Date, there's no way around this.

You are also doing correct.
But to get the result in the format you want, you need to use .format("/your format/") method after parsing the string.
String date = "15/12/2014 10:42:24";
SimpleDateFormat dateParser = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss");
SimpleDateFormat formatter = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Date parseDate = dateParser.parse(date);
formatter.format(parseDate) // this will change format of date as you want.

I don't think the way you parse is wrong. Are you sure you print orderDate right ?
The following code demonstrates both parsing and formatting (printing).
public static void main(String[] args) {
String format = "MM/dd/yyyy HH:mm:ss";
try {
SimpleDateFormat sdf = new SimpleDateFormat(format);
Date orderDate = new SimpleDateFormat(format).parse("04/15/2014 10:30:24");
System.out.println(sdf.format(orderDate));
} catch (Exception e) {
e.printStackTrace();
}
}

Provide Locale in the SimpleDateFormat constructor, otherwise parsing might be dependant on your local settings:
SimpleDateFormat sdf = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss", Locale.ROOT);

Java date format real simple

how would you write te date if i have a date and all i want is the month and the day like this (mm/dd) and then turn the month like this July, 08

Let me see if I understood well.
You have a date like "07/08" and you want "July, 08"?
You could try SimpleDateFormat
import java.text.SimpleDateFormat;
import java.text.ParseException;
class Test {
public static void main( String [] args ) throws ParseException {
SimpleDateFormat in = new SimpleDateFormat("MM/dd");
SimpleDateFormat out = new SimpleDateFormat("MMMM, dd");
System.out.println( out.format( in.parse("07/08") ) );
// Verbose
//String input = "07/09";
//Date date = in.parse( input );
//String output = out.format( date );
//System.out.println( output );
}
}

Use:
Format formatter = new SimpleDateFormat("MMMM, dd");
String s = formatter.format(date);
Formatting a Date Using a Custom Format

The SimpleDateFormat is your friend here. If you already have a java.util.Date object, just format it using the desired pattern (refer to the javadoc for details on date and time patterns):
SimpleDateFormat out = new SimpleDateFormat("MMMM, dd");
String s = out.format(date); // date is your existing Date object here
(EDIT: I'm adding some details as the original question is unclear and I may have missed the real goal.
If you have a String representation of a date in a given format (e.g. MM/dd) and want to transform the representation, you'll need 2 SimpleDateFormat as pointed out by others: one to parse the String into a Date and another one to format the Date.
SimpleDateFormat in = new SimpleDateFormat("MM/dd");
Date date = in.parse(dateAsString); // dateAsString is your String representation here
Then use the code snippet seen above to format it.)

the month and the day like this (mm/dd) and then turn the month like this July, 08
So you want to convert MM/dd to MMMM, dd? So you start with a String and you end up with a String? Then you need another SimpleDateFormat instance with the first pattern.
String dateString1 = "07/08";
Date date = new SimpleDateFormat("MM/dd").parse(dateString1);
String dateString2 = new SimpleDateFormat("MMMM, dd").format(date);
System.out.println(dateString2); // July, 08 (monthname depends on locale!).

Blackberry Java String to date conversion

I used following code to convert string to date but it is applying timezone of device while conversion.
I don't need this but I want same date/time from that string like
String = "2009-07-31 07:59:17.427"
Date = 2009-07-31 07:59:17.427
Date formatter = new Date(HttpDateParser.parse("2009-07-31 07:59:17.427"));
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
String strCustomDateTime = dateFormat.format(formatter);

You may take in account default timezone offset to date you get after parsing:
public static String StringToDate(String dateToParse) {
Date formatter = new Date(HttpDateParser.parse(dateToParse));
SimpleDateFormat dateFormat = new SimpleDateFormat(
"yyyy-MM-dd HH:mm:ss.SSS");
int offset = TimeZone.getDefault().getRawOffset();
formatter.setTime(formatter.getTime() + offset);
String strCustomDateTime = dateFormat.format(formatter);
return strCustomDateTime;
}

What is the problem, exactly? You are trying to convert "2009-07-31 07:59:17.427" into a point in time, but, this does not specify a unique point in time -- without a timezone. So you do need a timezone, and the library is necessary picking one, the platform's current timezone.
If the problem is you wish to specify a different time zone, then call DateFormat.setTimeZone():
format.setTimeZone(TimeZone.getTimeZone("your time zone"));