I am creating a log file to write out messages from a java program. However, since this java program will be running more than once a day, I would like to have just one log file per day. Therefore, I'd like to first check for a file if it exists for that day, and if it doesn't exist, then create the file and write to it. But if the file DOES exist, then I want to append to the file and keep the data previously written to it.