convert XMLGregorianCalendar to date i.e "MM/DD/YYYY hh:mm:ss AM"

You can do this to return a Date:

calendar.toGregorianCalendar().getTime()

I found that code from this tutorial. From there, you can use a SimpleDateFormat to turn it into a string in the format you want.

But, if you're using JDBC to save the date in the database, you probably can pass in the Date directly with this method:

preparedStatement.setDate(colNum, myDate);

Here is more clear answer:

Get instance of Date from XMLGregorianCalendar instance:

Date date = xmlCalendar.toGregorianCalendar().getTime();

I found that code from Convert XMLGregorianCalendar to Date in Java

Format that Date instance with format "MM/dd/yyyy hh:mm:ss a", you will get MM/DD/YYYY hh:mm:ss AM format

DateFormat  formatter = new SimpleDateFormat("MM/dd/yyyy hh:mm:ss a");
String formattedDate  = formatter.format(date)

From Convert Date to String in Java

For inserting database you would do what Daniel suggested

If you want to insert your date on a database I would first do what Daniel suggested:

XMLGregorianCalendar xgc=<assume this is initialized>;
Date timestamp=xgc.toGregorianCalendar().getTime();

and later insert it through a PreparedStatement as Timestamp in milliseconds (Epoch time). That way you won't loose precision.

preparedStatement.setTimestamp(colNum,new Timestamp(timestamp.getTime()));