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up vote 13 down vote favorite

So, I have an issue that really bothers me. I have a simple parser that I made in java. Here is the piece of relevant code:

while( (line = br.readLine())!=null)
{
    String splitted[] = line.split(SPLITTER);
    int docNum = Integer.parseInt(splitted[0].trim());
    //do something
}

Input file is CSV file, the first entry of the file being an integer. When I start parsing, I immidiately get this exception:

Exception in thread "main" java.lang.NumberFormatException: For input string: "1"
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Integer.parseInt(Integer.java:580)
at java.lang.Integer.parseInt(Integer.java:615)
at dipl.parser.TableParser.parse(TableParser.java:50)
at dipl.parser.DocumentParser.main(DocumentParser.java:87)

I checked the file, it indeed has 1 as its first value (no other characters are in that field), but I still get the message. I think that it may be because of file encoding: it is UTF-8, with Unix endlines. And the program is run on Ubuntu 14.04. Any suggestions where to look for the problem are welcome.

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7  
Nice one using copy and paste to put the error in the question! – T.J. Crowder 7 hours ago
up vote 28 down vote accepted

You have a BOM in front of that number; if I copy what looks like "1" in your question and paste it into vim, I see that you have a FE FF (e.g., a BOM) in front of it. From that link:

The exact bytes comprising the BOM will be whatever the Unicode character U+FEFF is converted into by that transformation format.

So that's the issue, consume the file with the appropriate reader for the transformation (UTF-8, UTF-16 big-endian, UTF-16 little-endian, etc.) the file is encoded with. See also this question and its answers for more about reading Unicode files in Java.

share|improve this answer
2  
That's a UTF-16 BOM. UTF-8 doesn't need a BOM, but if you add one the byte sequence is EF BB BF. – Doval 51 mins ago
1  
@Doval: Thank you, I was absolutely wrong to say it was a UTF-8 BOM, and you're quite right that on-the-wire, the BOM for UTF-8 is EF BB BF. But what we're looking at is the end result of reading the file and then seeing the output in the error message. The file might be in any transformation; all BOMs end up being FE FF once read. – T.J. Crowder 38 mins ago
    
But if it was read raw, then...oh, I don't know. :-) Could well have been UTF-16. :-) It'll all depend on how the file was read into the stream. – T.J. Crowder 21 mins ago

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