I'm trying to be able to replace a non printable character in a column. The character is � which I believe has a hex representation of FFFD. I've tried to use string manipulation and java snippet nodes with no success. I have to admit, I'm poor at regex. Any suggestions how to proceed?
The character 0xFFFD is the so-called "replacement character" in UTF-8. It is inserted into a character stream when an invalid UTF-8 character has been encountered.
You should probably check that your input data is actually UTF-8 and not some other encoding. If it is some other encoding, make sure that you read the data with that encoding. If it is UTF-8, then try to understand where the encoding errors come from.
I also tried to find a solution for replacing this character within KNIME but without any success. I guess this is not so easy because Java does not support unsigned binary data types and writing down the notation for a numerical value greater than 0x8F is difficult (because of two's complement).