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Does Java read 0xA0 as 0xFFFD?

One of my data processing modules crashed while reading ANSI input. Looking at the string in question using a hex viewer, there was a mysterious 0xA0 byte at the end of it.
Turns out this is
Unicode Character 'NO-BREAK SPACE' (U+00A0).
I tried replacing that:
String s = s.replace("\u00A0", "");
But it didn't work.
I then went and printed out what that character is using charAt and Java reports
65533
or 0xFFFD
(Unicode Character 'REPLACEMENT CHARACTER' (U+FFFD))
Plugging that into the replace code, I finally got rid of it!
But why do I see an 0xA0 in the file, but Java reads it as 0xFFFD?
BufferedReader r = new BufferedReader(new InputStreamReader(new FileInputStream(path), "UTF-8"));
String line = r.readLine();
while (line != null){
// do stuff
line = r.readLine();
}

U+FFFD is the "Unicode replacement character", which is generally used to represent "some binary data which couldn't be decoded correctly in the encoding you were using". (Sometimes ? is used for this instead, but U+FFFD is generally a better idea, as it's unambiguous.)
Its presence is usually a sign that you've tried to use the wrong encoding. You haven't specified which encoding you were using - or indeed how you were using it - but that's probably the problem. Check the encoding you're using and the encoding of the file. Be aware that "ANSI" isn't an encoding - there are lots of encodings which are known as ANSI encodings, and you'll need to pick the right one for your file.

How did you open the file?
If you use InputStreamReader(InputStream, CharSet) your can specify the 'true' charset of the file you would like to open. If you do not specify the charset yourself, java is using the default charset of your platform. On unix this is often UTF8 while on windows its often ISO8859.

throw exception when string is not encoded in UTF-8

I've got method where one of input attributes is String xml. I just want to create control for encoding of that xml. If any character is in other encoding that UTF-8, error will be thrown.
can you please tell me the easiest way how to create and test it?
I've used something like this:
String xml = IOUtils.toString(new FileInputStream("c:/encoding.xml"));
Document doc = builder.parse(IOUtils.toInputStream(xml, "UTF-8"));
added letters like Ľ,Š,Ť,Ž,ľ,š,ť,ž and save it as cp1250 file.
but no error.
what am I doing wrong?

This cannot be done natively in Java. A file is just a string of bytes, they can be interpreted however you feel like, Java by default has no way to add meaning. I recommend using this library (no I didn't write it):
http://code.google.com/p/juniversalchardet/
Follow these instructions (copy pasted from that link):
How to use it
Construct an instance of org.mozilla.universalchardet.UniversalDetector.
Feed some data (typically several thousands bytes) to the detector by calling UniversalDetector.handleData().
Notify the detector of the end of data by calling UniversalDetector.dataEnd().
Get the detected encoding name by calling UniversalDetector.getDetectedCharset().
Don't forget to call UniversalDetector.reset() before you reuse the detector instance.

String xml = IOUtils.toString(new FileInputStream("c:/encoding.xml"));
If this IOUtils is org.apache.commons.io.IOUtils then its Javadoc says
"Get the contents of an InputStream as a String using the default character encoding of the platform."
As you are saving as cp1250, I guess cp1250 is also your platform character encoding. What your code would be doing is
Read the file as a byte stream
Convert the byte stream to chars using cp1250 (platform encoding)
Transform the chars to Java internal representation (UTF-16)
Convert from UTF-16 to UTF-8
Create XML document
That will always work as cp1250 really is your file encoding, UTF-16 has every character in cp1250 and UTF-8 has every character in UTF-16.
If you want to read the bytes as UTF-8 and avoid automatic conversions, you should use one of the two-parameter variant of IOUtils.toString():
public static String toString(InputStream input, Charset encoding)
public static String toString(InputStream input, String encoding)
So I would try:
// Helper import: I always forget if the constant is "UTF8" or "UTF-8"
import org.apache.commons.lang.CharEncoding;
String xml = IOUtils.toString(new FileInputStream("c:/encoding.xml"), CharEncoding.UTF_8);
Document doc = builder.parse(IOUtils.toInputStream(xml, CharEncoding.UTF_8));
The rule of thumb here is: NEVER do any byte-to-string / string-to-byte conversion without specifying the source / destination encoding.
A minor rule of thumb would be: Unless you need to use some other encoding, use UTF-8 everywhere.
Both of those rules of thumb are independent of your programming language of choice.

UTF8 convertion for text obtained from internet

ElasticSearch is a search Server which accepts data only in UTF8.
When i tries to give ElasticSearch following text
Small businesses potentially in line for a lighter reporting load include those with an annual turnover of less than £440,000, net assets of less than £220,000 and fewer than ten employees"
Through my java application - Basically my java application takes this info from a webpage , and gives it to elasticSearch. ES complaints it cant understand £ and it fails. After filtering through below code -
byte bytes[] = s.getBytes("ISO-8859-1");
s = new String(bytes, "UTF-8");
Here £ is converted to �
But then when I copy it to a file in my home directory using bash and it goes in fine. Any pointers will help.

You have ISO-8895-1 octets in bytes, which you then tell String to decode as if it were UTF-8. When it does that, it doesn't recognize the illegal 0xA3 sequence and replaces it with the substitution character.
To do this, you have to construct the string with the encoding it uses, then convert it to the encoding that you want. See How do I convert between ISO-8859-1 and UTF-8 in Java?.

UTF-8 is easier than one thinks. In String everything is unicode characters.
Bytes/string conversion is done as follows.
(Note Cp1252 or Windows-1252 is the Windows Latin1 extension of ISO-8859-1; better use
that one.)
BufferedReader in = new BufferedReader(
new InputStreamReader(new FileInputStream(file), "Cp1252"));
PrintWriter out = new PrintWriter(
new OutputStreamWriter(new FileOutputStream(file), "UTF-8"));
response.setContentType("text/html; charset=UTF-8");
response.setEncoding("UTF-8");
String s = "20 \u00A3"; // Escaping
To see why Cp1252 is more suitable than ISO-8859-1:
http://en.wikipedia.org/wiki/Windows-1252

String s is a series of characters that are basically independent of any character encoding (ok, not exactly independent, but close enough for our needs now). Whatever encoding your data was in when you loaded it into a String has already been decoded. The decoding was done either using system default encoding (which is practically ALWAYS AN ERROR, do not ever use system default encoding, trust me I have over 10 years of experience in dealing with bugs related to wrong default encodings) or the encoding you explicitely specified when you loaded the data.
When you call getBytes("ISO-8859-1") for a String, you request that the String is encoded into bytes according to ISO-8859-1 encoding.
When you create a String from a byte array, you need to specify the encoding in which the characters in the byte array are represented. You create a string from a byte array that has been encoded in UTF-8 (and just above you encoded it in ISO-8859-1, that is your error).
What you want to do is:
byte bytes[] = s.getBytes("UTF-8");
s = new String(bytes, "UTF-8");

I have UTF-8 - but still get "Invalid byte 1 of 1-byte UTF-8 sequence"

I create a XML String on the fly (NOT reading from a file). Then I use Cocoon 3 to transform it via FOP to a PDF. Somewhere in the middle Xerces runs. When I use the hardcoded stuff everything works. As soon as I put a german Umlaut into the database and enrich my xml with that data I get:
Caused by: org.apache.cocoon.pipeline.ProcessingException: Can't parse the XML string.
at org.apache.cocoon.sax.component.XMLGenerator$StringGenerator.execute(XMLGenerator.java:326)
at org.apache.cocoon.sax.component.XMLGenerator.execute(XMLGenerator.java:104)
at org.apache.cocoon.pipeline.AbstractPipeline.invokeStarter(AbstractPipeline.java:146)
at org.apache.cocoon.pipeline.AbstractPipeline.execute(AbstractPipeline.java:76)
at de.grobmeier.tab.webapp.modules.documents.InvoicePipeline.generateInvoice(InvoicePipeline.java:74)
... 87 more
Caused by: com.sun.org.apache.xerces.internal.impl.io.MalformedByteSequenceException: Invalid byte 1 of 1-byte UTF-8 sequence.
at com.sun.org.apache.xerces.internal.impl.io.UTF8Reader.invalidByte(UTF8Reader.java:684)
at com.sun.org.apache.xerces.internal.impl.io.UTF8Reader.read(UTF8Reader.java:554)
I have then debugged my app and found out, my "Ä" (which comes frome the database) has the byte value of 196, which is C4 in hex. This is what I have expected according to this: http://www.utf8-zeichentabelle.de/
I do not know why my code fails.
I have then tried to add a BOM manually, like that:
byte[] bom = new byte[3];
bom[0] = (byte) 0xEF;
bom[1] = (byte) 0xBB;
bom[2] = (byte) 0xBF;
String myString = new String(bom) + inputString;
I know this is not exactly good, but I tried it - of course it failed. I have tried to add a xml header in front:
<?xml version="1.0" encoding="UTF-8"?>
Which failed too. Then I combined it. Failed.
After all I tried something like that:
xmlInput = new String(xmlInput.getBytes("UTF8"), "UTF8");
Which is doing nothing in fact, because it is already UTF-8. Still it fails.
So... any ideas what I am doing wrong and what Xerces is expecting from me?
Thanks
Christian

If your database contains only a single byte (with value 0xC4) then you aren't using UTF-8 encoding.
The character "LATIN CAPITAL LETTER A WITH DIAERESIS" has a code-point value U+00C4, but UTF-8 can't encode that in a single byte. If you check the third column "UTF-8 (hex.)" on UTF8-zeichentabelle.de you'll see that UTF-8 encodes that as 0xC3 84 (two bytes).
Please read Joel's article "The Absolute Minimum Every Software Developer Absolutely, Positively Must Know About Unicode and Character Sets (No Excuses!)" for more info.
EDIT: Christian found the answer himself; turned out it was a problem in the Cocoon 3 SAX component (I guess it's the alpha 3 version). It turns out that if you pass an XML as a String into the XMLGenerator class, something will go wrong during SAX parsing causing this mess.
I looked up the code to find the actual problem in Cocoon-stax:
if (XMLGenerator.this.logger.isDebugEnabled()) {
XMLGenerator.this.logger.debug("Using a string to produce SAX events.");
}
XMLUtils.toSax(new ByteArrayInputStream(this.xmlString.getBytes()), XMLGenerator.this.getSAXConsumer();
As you can see, the call getBytes() will create a Byte array with the JRE's default encoding which will then fail to parse. This is because the XML declares itself to be UTF-8 whereas the data is now in bytes again, and likely using your Windows codepage.
As a workaround, one can use the following:
new org.apache.cocoon.sax.component.XMLGenerator(xmlInput.getBytes("UTF-8"),
"UTF-8");
This will trigger the right internal actions (as Christian found out by experimenting with the API).
I've opened an issue in Apache's bug tracker.
EDIT 2: The issue is fixed and will be included in an upcoming release.

The C4 you see on that page refers to the unicode code point, U+00C4. The byte sequence used to represent such a code point in UTF-8 is NOT "\xC4". What you want is what's in the UTF-8 (hex.) column, namely "\xC3\x84".
Therefore, your data is not in UTF-8.
You can read about how data is encoded in UTF-8 here.

I'm running Windows 7 with TextPad as a text editor for manually building the xml data file. I was getting the MalformedByteSequenceException. My spec in the xml file was UTF-8. After poking around, I found that my editor had a tool "Tools ... Convert to DOS". I did that, re-saved the file, and the exception went away and my code ran fine.
I then looked at the default encoding for that file type in my editor. It was ASCII, though when I changed the xml encoding parameter to ASCII, I got another different MalformedByteSequenceException.
So on Windows systems, you might try keeping the xml encoding to UTF-8, but save the file encoded DOS. I did not dig any further as to why this works.

java unicode encoded file reading problem in jdk 1.3

I am using jdk1.3 for blackberry platform. Now I am facing a problem when I trying to read an Unicode encoded xml file.
My code :
java.io.BufferedReader br = new java.io.BufferedReader(new java.io.InputStreamReader(new java.io.FileInputStream(path),"UTF16"));
br.readLine();
Error:
sun.io.MalformedInputException: Missing byte-order mark
at sun.io.ByteToCharUnicode.convert(ByteToCharUnicode.java:123)
at java.io.InputStreamReader.convertInto(InputStreamReader.java:137)
at java.io.InputStreamReader.fill(InputStreamReader.java:186)
at java.io.InputStreamReader.read(InputStreamReader.java:249)
at java.io.BufferedReader.fill(BufferedReader.java:139)
at java.io.BufferedReader.readLine(BufferedReader.java:299)
at java.io.BufferedReader.readLine(BufferedReader.java:362)
Thanks

You XML file is missing a byte order mark.
In JDK 1.3, the byte order mark is mandatory if you use UTF-16. Try the UTF16-LE or -BE if you know in advance what the endianness is.
(The BOM is not mandatory in 1.4.2 and above.)
Of course, if your file is not UTF-16 at all, use the correct encoding. See the above link to character encodings. The actual encodings supported, apart from a small set of core encodings, are implementation defined so you'll need to check the docs for your particular JDK.
The encoding the files are in is supposed to be in the <xml> header of your files, something like:
<?xml version="1.0" encoding="THIS IS THE ENCODING YOU NEED TO USE"?>
If the file is in a single character encoding, or UTF-8 (without a BOM), You can try reading the first line with plain US-ASCII, it shouldn't contain any data outside that range. Parse the encoding field, then re-open the file with the deduced encoding.
This will only work if the actual encoding is supported by your platform obviously.
BTW: JDK 1.3 is ancient. Are you sure that's your version? (Doesn't change anything to the problem anyway except for the BOM part)

Try this code:
java.io.BufferedReader br = new java.io.BufferedReader(new java.io.InputStreamReader(new java.io.FileInputStream(path),"Windows-1256"));
br.readLine();