I'd need to see your code, to be sure, but it looks like you are now sending '3',, and . Those are 51, 10, and 13 in the ASCII table.
Your Processing code needs to read the whole string of data being sent, not one character at a time. Use the bufferUntil() method the the Serial class, in setup() to define when the serialEvent() callback is to be called.
Then, use readStringUntil() in serialEvent(). Then, use String::trim() to get rid of the and . Then, convert the String instance to an int.