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I try to convert a String to Date format in java but has an exception

I try to convert String to Date format but I got an exception!
Here is my code:
SimpleDateFormat format = new SimpleDateFormat("dd-MMM-yyyy");
startDate = format.parse(startDateString);
it should convert "14-MAY-2004" to Date. Thanks.

java.time
I recommend that you use java.time, the modern Java date and time API, for your date work.
DateTimeFormatter dateFormatter = new DateTimeFormatterBuilder()
.parseCaseInsensitive()
.appendPattern("d-MMM-uuuu")
.toFormatter(Locale.ENGLISH);
String startDateString = "14-MAY-2004";
LocalDate startDate = LocalDate.parse(startDateString, dateFormatter);
System.out.println(startDate);
Output is:
2004-05-14
Only if you indispensably need a Date object for a legacy API not yet upgraded to java.time, convert:
Instant startOfDay = startDate.atStartOfDay(ZoneId.systemDefault()).toInstant();
Date oldfashionedDate = Date.from(startOfDay);
System.out.println(oldfashionedDate);
Output in my time zone:
Fri May 14 00:00:00 CEST 2004
What went wrong in your code?
It’s almost certainly a locale problem. You didn’t specify a locale and hence no language for the month name or abbreviation. Always do that when the date string includes text in some language. Your SimpleDateFormat was using the default formatting locale of your JVM, and if that was a non-English-speaking locale, parsing was deemed to fail with an exception as you mentioned.
Links
Oracle tutorial: Date Time explaining how to use java.time.
Similar question: Java - Unparseable date

From the statment "it should convert 14-MAY-2004 to date" i assume your input string is 14-MAY-2004 and you want this string to be converted to Date
String js="14-May-2004";
Date dt=new Date(js);
LocalDateTime localDateTime=dt.toInstant().atZone(ZoneId.systemDefault()).toLocalDateTime();
localDateTime.format(DateTimeFormatter.ofPattern("dd-MM-yyyy"));//or in the same format use- "dd-MMM-yyyy"

Unable to obtain LocalDate from TemporalAccessor using quarters

I am trying to parse some date-string into a date value, however, using the below code, I am getting an exception:
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("Q'Q'uuuu - MMM");
String d = "3Q2016 - Aug";
System.out.println(LocalDate.parse(d, formatter));
The exception is below
java.time.format.DateTimeParseException: Text '3Q2016 - Aug' could not be parsed: Unable to obtain LocalDate from TemporalAccessor: {MonthOfYear=8, QuarterOfYear=3, Year=2016},ISO of type java.time.format.Parsed
Looking at the exception, I see the correct data, but it is not able to be parsed for some reason.
Other similar topics i see suggest using LocalDate or LocalDateTime, but neither work.

Its because the specified string does not have a specific date to select. You probably need to use YearMonth instead of LocalDateTime and then convert it using YearMonth.atDay(1) to get the first day of the month.

As said in this answer, you need to specify a day to be able to parse to a LocalDate. So one solution is to parse to a YearMonth instead and convert to a LocalDate by specifying a day afterwards.
Or you create a DateTimeFormatter with a fixed day in the first place:
DateTimeFormatter formatter = new DateTimeFormatterBuilder()
.appendPattern("Q'Q'uuuu - MMM")
.parseDefaulting(ChronoField.DAY_OF_MONTH, 1)
.toFormatter(Locale.US);
String d = "3Q2016 - Aug";
System.out.println(LocalDate.parse(d, formatter));
I used toFormatter(Locale.US) to make the example work in all environments. In an environment where the input string matches the current locale, you can use toFormatter() instead.

Try adding a Time part to the date -
String str = "2Q1986 - Apr - 08 T00:00";
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("Q'Q'yyyy - MMM - dd 'T'hh:mm");
LocalDate dateTime = LocalDate.parse(str, formatter);

Parsing from SimpleDateFormat to Date not working?

SimpleDateFormat df = new SimpleDateFormat();
Date lastLogin = null;
try {
String troubleChild = lineScanner.next();
lastLogin = df.parse(troubleChild);
} catch (ParseException e) {
System.out.println("ohnoes");
}
Hi I'm quite new to using the date functions and I've come up with a problem. I have a file that is being parsed into various variables and they all work except this one i can never get it so that it passes the try/catch clause i've looked up similar problems but none of them work on my code.(The date i am inputting is in the format: Mon, Oct 30 22:20:11 GMT 2017) please can I get some help and thanks for it!

Solution: java.time
Please don’t take the trouble with the long outmoded classes Date and SimpleDateFormat. Instead use java.time, the modern Java date and time API also known as JSR-310:
DateTimeFormatter dtf
= DateTimeFormatter.ofPattern("E, MMM d H:mm:ss z uuuu", Locale.UK);
String inputDate = "Mon, Oct 30 22:20:11 GMT 2017";
ZonedDateTime lastLogin = ZonedDateTime.parse(inputDate, dtf);
System.out.println(lastLogin);
This prints
2017-10-30T22:20:11Z[GMT]
Since dates and times may come in so many different textual formats, I am using a format pattern string to specify your particular format. For which letters you may use, and what difference it makes whether you use 1, 3 or 4 of the same letter, see the documentation. Beware that format pattern strings are case sensitive.
Problem: SimpleDateFormat
You used the no-arg SimpleDateFormat constructor. The way I read the documentation, this gives you the default date format for your locale. If your JVM is running UK locale, I believe the format goes like 28/11/17 10:57 — not much like the input format you were trying to parse. You can use System.out.println(df.format(new Date())); to find out. The usual SimpleDateFormat constructor to use would be SimpleDateFormat(String, Locale) so that you may again supply a format pattern string and a locale.

Joda-Time Formatter with a dateStyle and a timeStyle

With java.text.DateFormat, it's possible to build a date formatter with a date and a time style :
DateFormat df = getDateTimeInstance(DateFormat.SHORT, DateFormat.LONG);
system.out.println(df.format(new Date()));
Is it possible to use something similar with Joda-Time ?

Standard Formatting Built Into JodaTime
There's a bunch of standard Date and Time formats built right into JodaTime.
Here's an example of one that I use:
DateTime dateTime = DateTime.now(DateTimeZone.UTC);
String formattedDateTime = dateTime.toString(DateTimeFormat.fullDateTime());
Notice the DateTimeFormat.fullDateTime().
Some other options for this include:
fullTime()
fullDate()
shortDateTime()
forStyle("MS") Indicates a Medium Date and a Short Time.
forStyle("S-") Indicates a Short Date and No Time.
... etc ...
The full listing can be found at:
http://www.joda.org/joda-time/apidocs/org/joda/time/format/DateTimeFormat.html#forStyle(java.lang.String)
Cheers,
JP

Use DateTimeFormat.forPattern() with a pattern that does what you want.
For instance, DateTimeFormat.forPattern("YYYY-MM-dd HH:mm:ss");

How to parse month full form string using DateFormat in Java?

I tried this:
DateFormat fmt = new SimpleDateFormat("MMMM dd, yyyy");
Date d = fmt.parse("June 27, 2007");
error:
Exception in thread "main" java.text.ParseException: Unparseable date: "June 27, 2007"
The java docs say I should use four characters to match the full form.
I'm only able to use MMM successfully with abbreviated months like "Jun" but i need to match full form.
Text: For formatting, if the number
of pattern letters is 4 or more, the
full form is used; otherwise a short
or abbreviated form is used if
available. For parsing, both forms are
accepted, independent of the number of
pattern letters.
https://docs.oracle.com/javase/6/docs/api/java/text/SimpleDateFormat.html

You are probably using a locale where the month names are not "January", "February", etc. but some other words in your local language.
Try specifying the locale you wish to use, for example Locale.US:
DateFormat fmt = new SimpleDateFormat("MMMM dd, yyyy", Locale.US);
Date d = fmt.parse("June 27, 2007");
Also, you have an extra space in the date string, but actually this has no effect on the result. It works either way.

LocalDate from java.time
Use LocalDate from java.time, the modern Java date and time API, for a date
DateTimeFormatter dateFormatter = DateTimeFormatter.ofPattern("MMMM d, u", Locale.ENGLISH);
LocalDate date = LocalDate.parse("June 27, 2007", dateFormatter);
System.out.println(date);
Output:
2007-06-27
As others have said already, remember to specify an English-speaking locale when your string is in English. A LocalDate is a date without time of day, so a lot better suitable for the date from your string than the old Date class. Despite its name a Date does not represent a date but a point in time that falls on at least two different dates in different time zones of the world.
Only if you need an old-fashioned Date for an API that you cannot afford to upgrade to java.time just now, convert like this:
Instant startOfDay = date.atStartOfDay(ZoneId.systemDefault()).toInstant();
Date oldfashionedDate = Date.from(startOfDay);
System.out.println(oldfashionedDate);
Output in my time zone:
Wed Jun 27 00:00:00 CEST 2007
Link
Oracle tutorial: Date Time explaining how to use java.time.

Just to top this up to the new Java 8 API:
DateTimeFormatter formatter = new DateTimeFormatterBuilder().appendPattern("MMMM dd, yyyy").toFormatter();
TemporalAccessor ta = formatter.parse("June 27, 2007");
Instant instant = LocalDate.from(ta).atStartOfDay().atZone(ZoneId.systemDefault()).toInstant();
Date d = Date.from(instant);
assertThat(d.getYear(), is(107));
assertThat(d.getMonth(), is(5));
A bit more verbose but you also see that the methods of Date used are deprecated ;-) Time to move on.

val currentTime = Calendar.getInstance().time
SimpleDateFormat("MMMM", Locale.getDefault()).format(date.time)