convert-date.java

// Imports required
import java.text.SimpleDateFormat;
import java.text.ParseException;

/**
 * Convert a date to a different format.
 *
 * @param  currentFormat The current date format
 * @param  newFormat     The new date format
 * @param  subject       The date that's going to be converted
 * @return The new data as a string
 * @throws ParseException If the conversion fails (Invalid date format)
 */
final public static String convertDate(String currentFormat, String newFormat, String subject)
    throws ParseException
{
    return new SimpleDateFormat(newFormat).format(
        new SimpleDateFormat(currentFormat).parse(subject)
    ).toString();
}