The convertDateTime is an excellent tag which I use widely in my project. Probably you might have encountered some problem in setting the date object.
1. If you are getting the date from the database whic is of type 'timestamp' or 'Date', then we need to convert the obtained date to java.util.Date.
If timestamp,
TimeStamp time = <timestamp from database>
new Date(time.getTime());
This snippet will work while using convertDateTime in the frontend.
If 'Date',
Just a typecast would suffice
2. If you are mannually setting the date in the java code, make sure you set the time information also; else the time information will show as 00:00:00 in the page. I dont think there are any way in which the time information gets lost.
3. If you are getting date in the form of
string[say from Mainframe, or an inputText], then you can use simpleDateFormatter to convert.
Hope I have answered your question