Develop Reference

issue in converting the date from string to date type

below is the code I have used to add the number of days to the existing date..which gave me string output and I want that to be converted to Date format again...I have tried formating but it gave the out put -->
Date date = sdf.parse(dt);
sysout (date ) --giving me -- Mon May 05 00:00:00 PDT 2008
but I want it as YYYY-MM/DD
sdf.format(date) --Gives me 2008-05-05 which I am looking but it is a string object...but I want this to be converted to DATE type
String dt = "2008-01-01"; // Start date
System.out.println("start date "+dt);
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
Calendar c = Calendar.getInstance();
c.setTime(sdf.parse(dt));
c.add(Calendar.DATE, 125); // number of days to add
dt = sdf.format(c.getTime());
System.out.println("c.getTime() "+c.getTime());
System.out.println("end date "+dt);
Date date = sdf.parse(dt);
System.out.println("last but one date in DATE form -->" +date);
System.out.println("last formatted date in string form "+sdf.format(date));

You created the format right.
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
but you are using it incorrectly. you should use
sdf.format(your_unformated_date);

Here is a sample code that will convert date from String to Date type using SimpleDateFormat Class:
public static void convert()
{
String str="10:25:35";
SimpleDateFormat sdf=new SimpleDateFormat("hh:mm:ss");
System.out.println(sdf.format(str));
}

convert a date object to Oracle timestamp type string

I want to convert a date object, ex: new Date(), to a string which has a format like Oracle's time stamp type, ex: 21-OCT-13 11.08.13.858000000 AM. I know I could just get each piece of information in the date object like day, month, year, hour, minute, ... to form the Oracle format string but I really want to know is there a utility to do that instead?

Using SimpleDateFormat#format() you would print a Date as
SimpleDateFormat sdf = new SimpleDateFormat("dd-MMM-yy hh.mm.ss.SSSSSSSSS a");
System.out.println(sdf.format(new Date()).toUpperCase());
Output :
21-OCT-13 10.01.38.000000614 AM
See JavaDocs for Date and Time patterns.

Try taking a look at SimpleDateFormats - That would be your best bet and easiest way of doing it.
Eg:
Date date = new Date();
SimpleDateFormat dateFormat = new SimpleDateFormat("hh:mm:ss"); //Hours:Minutes:Seconds
String strDate = dateFormat.format(date);

Use SimpleDateFormat.
Date date = new Date();
SimpleDateFormat sdf = new SimpleDateFormat("your_format_here"); // dd/MM/yy h:mm:ss a
String formattedDate = sdf.format(date);
System.out.println(formattedDate);

Set a String variable to a Date object in java

I want to set a hand written String as the date for a Date object. What I'm trying to say is that I want to do is this:
String date= [date string here!!!];
Date mydate = new Date(date);
Something like that. The reason I want to do this is because I want my network to have standard Date and Time because since I run them from the same machine the time is being taken from the same clock and it gets different time every time. So I want to get that time and also add 1-2 seconds in the end so I can test my nodes with different times.

Java is strongly typed language. You cannot assign string to Date. However you can (and should) parse string into date. For example you can use SimpleDateFormat class like the following:
SimpleDateFormat fmt = new SimpleDateFormat("yyyy-MM-dd");
Date date = fmt.parse("2013-05-06");

you'll want to use dateformatter
DateFormat formatter = new SimpleDateFormat("MM/dd/yy");
Date date = formatter.parse("01/29/02");

String string = "January 2, 2010";
Date date = new SimpleDateFormat("MMMM d, yyyy", Locale.ENGLISH).parse(string);
System.out.println(date); // Sat Jan 02 00:00:00 BOT 2010
updated
String string ="2013-04-26 08:34:55.705"
Date date = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS").parse(string);
System.out.println(date);

Calender issue with time zone

I'm having a weird situation with Java Calendar. I'm using dozer mapper to map the objects.
I want to write a method that will convert this object to the following format. yyyy-MM-dd'T'HH:mm:ss.SSS'Z'
say element 2010-11-11T09:30:47.000Z
public Calender getValue(Date source,Calender c) {
Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("GMT"));
calendar.setTime(source);
return calendar;
}
When I run the program, it is printing
2010-11-11T04:00:47.000Z - Because we are setting the Timezone to be GMT, (9.30 - 5.30 = 4.00)
I want my object to have same format and value.if I don't set TimeZone to GMT, it will show as 2008-11-21T09:30:47.000+05:30.
I want it as 2010-11-11T09:30:47.000Z.
I tried added 5.30 to calender.
calendar.add(Calendar.HOUR, 5);
calendar.add(Calendar.MINUTE, 30)
then it works.But if this is ran from any other place, difference won't be 5.30.So I cannot add 5.30 to calenderget
Is there any way to get rid of this problem? I want to return Calender object.
Any suggestions or help would be much appreciated

Use a pattern. F.E:
String pattern = "yyyy-MM-dd'T'HH:mm:ssZ";
DateTimeFormatter dtf = DateTimeFormat.forPattern(pattern);
Also,
SimpleDateFormat dateformatyyyyMMdd = new SimpleDateFormat("yyyyMMdd");
String date_to_string = dateformatyyyyMMdd.format(dateNow);

you can use SimpleDateFormat like this.
SimpleDateFormat formatter, FORMATTER;
formatter = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
String oldDate = "2011-03-10T11:54:30.207Z";
Date date = formatter.parse(oldDate.substring(0, 24));
FORMATTER = new SimpleDateFormat("dd-MMM-yyyy HH:mm:ss.SSS");
System.out.println("OldDate-->"+oldDate);
System.out.println("NewDate-->"+FORMATTER.format(date));
Output OldDate-->2011-03-10T11:54:30.207Z NewDate-->10-Mar-2011 11:54:30.207

Current Date & Time in Java

I want the current date and time in the following format :
Date :YYYYMMDD
Time : HHMMSS
I tried the following
DateFormat dateFormat = new SimpleDateFormat("yyyyMMdd");
//get current date time with Date()
Date date = new Date();
System.out.println(dateFormat.format(date));
//get current date time with Calendar()
Calendar cal = Calendar.getInstance();
System.out.println(new Date().getTime());
By this I am getting the desired date output but the time is coming in this way 1341837848290.
The expected is HHMMSS.

Use format()
System.out.println(new SimpleDateFormat("HH:mm:SS").format(new Date()));
Date instance doesn't have any property to hold custom format, So you need to format the date instance to String with your custom format HH:mm:SS (See API doc for more detail)
See
IDEOne demo

try this
DateFormat dateFormat = new SimpleDateFormat("yyyyMMdd");
//get current date time with Date()
Date date = new Date();
System.out.println(dateFormat.format(date));
//get current date time with Calendar()
DateFormat timeFormat = new SimpleDateFormat("HHmmss");
Date d=new Date();
System.out.println(timeFormat.format(d);

Did you check out the joda-time library? Link here
With joda-time, you could easily call new DateTime(), call toString() on it and have this output, which may be more what you want:
public static void main(final String[] args) {
final DateTime d = new DateTime();
System.out.println(d.toString());
}
Output: 2012-07-09T14:54:13.366+02:00
Joda-Time is very powerful on the plus side. Of course, this is an extra lib you need to include, and if this is not possible or desired, another approach would probably be better.

I tried this:
SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd HHmmss");
Date date = Calendar.getInstance().getTime();
System.out.println(sdf.format(date));
Yields:
20120709 145518
First section is the date (20120709), the second section is the time(145518).
It seems that you have been using the wrong notation. I would recommend you take a look here for full details.

DateFormat dateFormat = new SimpleDateFormat("yyyyMMdd HH:mm:SS");
//get current date time with Date()
Date date = new Date();
System.out.println(dateFormat.format(date));
for more formatting refer API Doc