Date format return wrong date

Question

I'm trying to format a Date object and convert that formatted one back to Date type object
This is my code

SimpleDateFormat inputDf = new SimpleDateFormat("EEE MMM dd yyyy HH:mm:ss zzz");
System.out.println("before format  "+invoiceDate);
invoiceDate=inputDf.parse(inputDf.format(invoiceDate));
System.out.println("after format "+inputDf.format(invoiceDate));
System.out.println("after parse "+invoiceDate);

Out put from above code is

before format : Mon Jan 14 10:55:40 IST 2013
after format  : Mon Jan 14 2013 10:55:40 IST
after parse   : Mon Jan 14 10:55:40 IST 2013

You can see here after i parse the date object it converting back to original format(format which shows before format) but i want Date object like it appear in second print line(after format) thing is .format method returns String not a Date object, how can i fix this ?

Thanks

Answer 1

This behaviour is because the SimpleDateFomat does not impose itself upon the date. The SimpleDateFormat is merely a pattern to get a formated output out of any Date, but it does not change the date itself. Date does not have a format, so

System.out.println("before format  "+invoiceDate);

defaults to the default pattern format.

Actually, the SimpleDateFormat is exactly the way to achieve what you want, ie use it to properly format your output everytime you need it. Formating a date object gives you a representation of it, a String.