Develop Reference

Naming a file using unicode characters in java

I learnt that, Java allows file names to have unicode characters.
How to name a file,
naïve.java,
using english keyboard?
Is there a notation similar to unicode escape notation(used in java source code) that we can use to name java files with unicode characters?

It seems that you are referring to JLS §7.2 “Host Support for Packages”:
A package name component or class name might contain a character that cannot correctly appear in a host file system's ordinary directory name, such as a Unicode character on a system that allows only ASCII characters in file names. As a convention, the character can be escaped by using, say, the # character followed by four hexadecimal digits giving the numeric value of the character, as in the \uxxxx escape (§3.3).
Under this convention, the package name:
children.activities.crafts.papierM\u00e2ch\u00e9
which can also be written using full Unicode as:
children.activities.crafts.papierMâché
might be mapped to the directory name:
children/activities/crafts/papierM#00e2ch#00e9
Note that this is described as a convention and only for characters not being supported by the host’s filesystem. So the first obstacle is to find a system without Unicode support in the file system API before you can check whether javac still adheres to this convention.
So for most systems, if you want to name a file naïve.java, there’s not only support to name it directly that way, you also have to name it that way as the fallback escaping scheme is not supported by tools designed to run only on systems which don’t need it.
That leads to your other question about how to enter it via the keyboard. Well, that’s system dependent. The most portable solution is:
open your browser
navigate to this question and mark naïve.java with the mouse
press ctrl+c
use your favorite tool to create a new .java file
when asked for the new name, press ctrl+v
As a general solution, refrain from using every feature, the Java programming language offers…

All String objects in Java contain UTF-16 Unicode. All Java objects that open files eventually name those files strings.
However, your keyboard is not Java's problem, it's your operating system's problem.
So:
File foo = new File("n\u00e4ive.java");
You edited the question to say that what you really want is to have a Java source file with interesting characters. That's a matter for your favorite text editor and operating system.
Java is perfectly happy to compile files with arbitrary names. However, creating those files and managing those files is not its problem. How you would go about creating such a file is between you and your operating system. Windows, Linux, OSX: all have different tools for entering Unicode characters that aren't part of the obvious keyboard map.

Java UTF8 encoding issues with Storm

Pretty desperate for help after 2 days trying to debug this issue.
I have some text that contains unicode characters, for example, the word:
korte støvler
If I run code that writes this word to a file on one of the problem machines, it works correctly. However, when I write the file exactly the same way in a storm bolt, it does not encode correctly, and the ø character is replaced with question marks.
In the storm_env.ini file I have set
STORM_JAR_JVM_OPTS:-Dfile.encoding=UTF-8
I also set the encoding as UTF-8 in the code, and in mvn when it is packaged.
I have run tests on the boxes to check JVM default encodings, and they are all UTF-8.
I have tried 3 different methods of writing the file and all cause the same issue, so it is definitely not that.

This issue was fixed by simply build another machine on ec2. It had exactly the same software versions and configuration as the boxes with issues.

Cannot verify text which contains diacritics

I am using selenium webdriver with java and trying to verify some texts I find on a page.
The text contains diacritics like ţ ă etc.
The problem I encounter is when I run my test from the command line using maven; I need to do this because I will be integrating them into Jenkins.
So I have a simple assert in my test:
Assert.assertEquals("some text with ţ", driver.findElement(text).getText());
which fails and I don't know what is the right way to make this work.
I have read that the default encoding for strings in Java is UTF-16, so when the text is taken from the page with getText, the string is already encoded and I suppose that means that the characters are lost. On the other hand, I don't know if the comparing text itself "some text with ţ" is interpreted ok.
Has anyone had problems similar to this? And how have you solved them?
Thanks

Maven is even issuing a warning specific to your error:
WARNING: character encoding not set. Using the platform default encoding, i.e., the
build is platform-dependent!
or a similar message.
The solution is to:
make sure you save the Java source code files in UTF-8;
make sure you explicitly configure the encoding in pom.xml (a setting on the Compiler plugin).

Encoding issue on filename with Java 7 on OSX with jnlp/webstart

I have this problem that has been dropped on me, and have been a couple of days of unsuccessful searches and workaround attempts.
I have now an internal java swing program distributed by jnlp/webstart, on osx and windows computers, that, among other things, downloads some files from WebDav.
Recently, on a test machine with OSX 10.8 and Java 7, filenames and directory names with accented characters started having those replaced by question marks.
No problem on OSX with versions of Java before 7.
example :
XXXYYY_è_ABCD/
becomes
XXXYYY_?_ABCD/
using java.text.Normalizer (NFD, NFC, NFKD, NFKC) on the original string, the result is different but still wrong :
XXXYYY_e?_ABCD/
or
XXXYYY_e_ABCD/
I know, from correspondence between [andrew.brygin at oracle.com] and [mik3hall at gmail.com] that
Yes, file.encoding is set based on the locale that the jvm is running
on, and if you run your java vm in xxxx.UTF-8 locale, the
file.encoding should be UTF-8, set to MacRoman will be problematic.
So I believe Oracle/OpenJDK7 behaves correctly. That said, as Andrew
Thompson pointed out, if all previous Apple JDK releases use MacRoman
as the file.encoding for english/UTF-8 locale, there is a
"compatibility" concern here, it might worth putting something in the
release note to give Oracle/OpenJDK MacOS user a heads up.
original mail
from Joni Salonen blog (java-and-file-names-with-invalid-characters) i know that :
You probably know that Java uses a “default character encoding” to
convert binary data to Strings. To read or write text using another
encoding you can use an InputStreamReader or OutputStreamWriter. But
for data-to-text conversions deep in the API you have no choice but to
change the default encoding.
and
What about file.encoding?
The file.encoding system property can also be used to set the default
character encoding that Java uses for I/O. Unfortunately it seems to
have no effect on how file names are decoded into Strings.
executing locale from inside the jnlp invariabily prints
LANG=
LC_COLLATE="C"
LC_CTYPE="C"
LC_MESSAGES="C"
LC_MONETARY="C"
LC_NUMERIC="C"
LC_TIME="C"
LC_ALL=
the most similar problem on stackoverflow with a solution is this :
encoding-issues-on-java-7-file-names-in-os-x
but the solution is wrapping the execution of the java program in a script with
#!/bin/bash
export LC_CTYPE="UTF-8" # Try other options if this doesn't work
exec java your.program.Here
but I don't think this option is available to me because of the webstart, and I haven't found any way to set the LC_CTYPE environment variable from within the program.
Any solutions or workarounds?
P.S. :
If we run the program directly from shell, it writes the file/directory correctly even on OSX 10+Java 7.
The problem appears only with the combination of JNLP+OSX+Java7

I take it it's acceptable to have maximal ASCII representation of the file name, which works in virtually any encoding.
First, you want to use specifically NFKD, so that maximum information is retained in the ASCII form. For example, "2⁵" becomes "25"rather than just
"2", "fi" becomes "fi" rather than "" etc once the non-ascii and non-control characters are filtered out.
String str = "XXXYYY_è_ABCD/";
str = Normalizer.normalize(str, Normalizer.Form.NFKD);
str = str.replaceAll( "[^\\x20-\\x7E]", "");
//The file name will be XXXYYY_e_ABCD no matter what system encoding
You would then always pass filenames through this filter to get their filesystem name. You only lose is some uniqueness, I.E file asdé.txt is the same
as asde.txt and in this system they cannot be differentiated.

EDIT: After experimenting with OS X some more I realized my answer was totally wrong, so I'm redoing it.
If your JVM supports -Dfile.encoding=UTF-8 on the JVM command line, that might fix the issue. I believe that is a standard property but I'm not certain about that.
HFS Plus, like other POSIX-compliant file systems, stores filenames as bytes. But unlike Linux's ext3 filesystem, it forces filenames to be valid decomposed UTF-8. This can be seen here with the Python interpreter on my OS X system, starting in an empty directory.
$ python
Python 2.7.1 (r271:86832, Jul 31 2011, 19:30:53)
>>> import os
>>> os.mkdir('\xc3\xa8')
>>> os.mkdir('e\xcc\x80')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
OSError: [Errno 17] File exists: 'e\xcc\x80'
>>> os.mkdir('\x8f')
>>> os.listdir('.')
['%8F', 'e\xcc\x80']
>>> ^D
$ ls
%8F è
This proves that the directory name on your filesystem cannot be Mac-Roman encoded (i.e. with byte value 8F where the è is seen), as long as it's an HFS Plus filesystem. But of course, the JVM is not assured of an HFS Plus filesystem, and SMB and NFS do not have the same encoding guarantees, so the JVM should not assume this scheme.
Therefore, you have to convince the JVM to interpret file and directory names with UTF-8 encoding, in order to read the names as java.lang.String objects correctly.

Shot in the dark: File Encoding does not influence the way how the file names are created, just how the content gets written into the file - check this guy here: http://jonisalonen.com/2012/java-and-file-names-with-invalid-characters/
Here is a short entry from Apple: http://developer.apple.com/library/mac/#qa/qa1173/_index.html
Comparing this to http://docs.oracle.com/javase/tutorial/i18n/text/normalizerapi.html I would assume you want to use
normalized_string = Normalizer.normalize(target_chars, Normalizer.Form.NFD);
to normalize the file names before you pass them to the File constructor. Does this help?

I don't think there is a real solution to this problem, right now.
Meantime I came to the conclusion that the "C" environment variables printed from inside the program are from the Java Web Start sandbox, and (by design, apparently) you can't influence those using the jnlp.
The accepted (as accepted by the company) workaround/compromise was of launching the jnlp using javaws from a bash script.
Apparently, launching the jnlp from browser or from finder creates a new sandbox environment with the LANG not setted (so is setted to "C" that is equal to ASCII).
Launching the jnlp from command line instead prints the right LANG from the system default, inheriting it from the shell.
This permits to at least preserve the autoupdating feature of the jnlp and dependencies.
Anyway, we sent a bug report to Oracle, but personally I'm not hoping it to be resolved anytime soon, if ever.

It's a bug in the old-skool java File api, maybe just on a mac? Anyway, the new java.nio api works much better. I have several files containing unicode characters and content that failed to load using java.io.File and related classes. After converting all my code to use java.nio.Path EVERYTHING started working. And I replaced org.apache.commons.io.FileUtils (which has the same problem) with java.nio.Files...
...and be sure to read and write the content of file using an appropriate charset, for example:
Files.readAllLines(myPath, StandardCharsets.UTF_8)

Java application failing on special characters

An application I am working on reads information from files to populate a database. Some of the characters in the files are non-English, for example accented French characters.
The application is working fine in Windows but on our Solaris machine it is failing to recognise the special characters and is throwing an exception. For example when it encounters the accented e in "Gérer" it says :-
Encountered: "\u0161" (353), after : "\'G\u00c3\u00a9rer les mod\u00c3"
(an exception which is thrown from our application)
I suspect that in order to stop this from happening I need to change the file.encoding property of the JVM. I tried to do this via System.setProperty() but it has not stopped the error from occurring.
Are there any suggestions for what I could do? I was thinking about setting the basic locale of the solaris platform in /etc/default/init to be UTF-8. Does anyone think this might help?
Any thoughts are much appreciated.

That looks like a file that was converted by native2ascii using the wrong parameters. To demonstrate, create a file with the contents
Gérer les modÚ
and save it as "a.txt" with the encoding UTF-8. Then run this command:
native2ascii -encoding windows-1252 a.txt b.txt
Open the new file and you should see this:
G\u00c3\u00a9rer les mod\u00c3\u0161
Now reverse the process, but specify ISO-8859-1 this time:
native2ascii -reverse -encoding ISO-8859-1 b.txt c.txt
Read the new file as UTF-8 and you should see this:
Gérer les modÀ\u0161
It recovers the "é" okay, but chokes on the "Ú", like your app did.
I don't know what all is going wrong in your app, but I'm pretty sure incorrect use of native2ascii is part of it. And that was probably the result of letting the app use the system default encoding. You should always specify the encoding when you save text, whether it's to a file or a database or what--never let it default. And if you don't have a good reason to choose something else, use UTF-8.

Try to use
java -Dfile.encoding=UTF-8 ...
when starting the application in both systems.
Another way to solve the problem is to change the encoding from both system to UTF-8, but i prefer the first option (less intrusive on the system).
EDIT:
Check this answer on stackoverflow, It might help either:
Changing the default encoding for String(byte[])

Instead of setting the system-wide character encoding, it might be easier and more robust, to specify the character encoding when reading and writing specific text data. How is your application reading the files? All the Java I/O package readers and writers support passing in a character encoding name to be used when reading/writing text to/from bytes. If you don't specify one, it will then use the platform default encoding, as you are likely experiencing.
Some databases are surprisingly limited in the text encodings they can accept. If your Java application reads the files as text, in the proper encoding, then it can output it to the database however it needs it. If your database doesn't support any encoding whose character repetoire includes the non-ASCII characters you have, then you may need to encode your non-English text first, for example into UTF-8 bytes, then Base64 encode those bytes as ASCII text.
PS: Never use String.getBytes() with no character encoding argument for exactly the reasons you are seeing.

I managed to get past this error by running the command
export LC_ALL='en_GB.UTF-8'
This command set the locale for the shell that I was in. This set all of the LC_ environment variables to the Unicode file encoding.
Many thanks for all of your suggestions.

You can also set the encoding at the command line, like so java -Dfile.encoding=utf-8.

I think we'll need more information to be able to help you with your problem:
What exception are you getting exactly, and which method are you calling when it occurs.
What is the encoding of the input file? UTF8? UTF16/Unicode? ISO8859-1?
It'll also be helpful if you could provide us with relevant code snippets.
Also, a few things I want to point out:
The problem isn't occurring at the 'é' but later on.
It sounds like the character encoding may be hard coded in your application somewhere.

Also, you may want to verify that operating system packages to support UTF-8 (SUNWeulux, SUNWeuluf etc) are installed.

Java uses operating system's default encoding while reading and writing files. Now, one should never rely on that. It's always a good practice to specify the encoding explicitly.
In Java you can use following for reading and writing:
Reading:
BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(inputPath),"UTF-8"));
Writing:
PrintWriter pw = new PrintWriter(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(outputPath), "UTF-8")));