Some suggestions:
- rename your method to "toRequiredFormat" or simply "format".
Java supports method overloading, so you don't need to specify twice that this method takes a Calendar (once in the parameter list, once in the name).
- don't throw Exception; throw ParseException instead as that's the actual exception type being thrown.
- don't ever write code like this again:
You will loose all information on the message except the message. Better alternatives:
or even simpler