toRealPath（），IO / NIO包Java

Question

I have just read on this tutorial that toRealPath(), should give back the absolute path if the file that the path refers to really exists.

Here is a snippet from the same tutorial:

try {
       Path fp = path.toRealPath(); } catch (NoSuchFileException x) {
       System.err.format("%s: no such" + " file or directory%n", path);
       // Logic for case when file doesn't exist. } catch (IOException x) {
       System.err.format("%s%n", x);
       // Logic for sort of file error. }

So, now when I use an existing file located on my desktop for example ( Path inputPath = Paths.get("/home/user/Desktop/indeed.txt" ); It gives me an exception like if it did not exist. What may cause this problem? Thanks a lot in advance indeed.

EDIT: I get a NoSuchFileException out of it.

java.nio.file.NoSuchFileException: /home/user/Desktop/indeed.txt
    at sun.nio.fs.UnixException.translateToIOException(UnixException.java:86)
    at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:102)
    at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:107)
    at sun.nio.fs.UnixPath.toRealPath(UnixPath.java:833)
    at Pathss.main(Pathss.java:25)

Answer 1

Can you tell us the exact exception thrown? As tutorial you mentioned says:

This method throws an exception if the file does not exist or cannot be accessed.

So it may be that you simply cannot access that file.

Answer 2

according the source of jdk, the translateToIOException method is implemented like this:

private IOException translateToIOException(String file, String other) {
    // created with message rather than errno
    if (msg != null)
        return new IOException(msg);

    // handle specific cases
    if (errno() == UnixConstants.EACCES)
        return new AccessDeniedException(file, other, null);
    if (errno() == UnixConstants.ENOENT)
        return new NoSuchFileException(file, other, null);
    if (errno() == UnixConstants.EEXIST)
        return new FileAlreadyExistsException(file, other, null);

    // fallback to the more general exception
    return new FileSystemException(file, other, errorString());
}

You can view the whole source at here http://grepcode.com/file/repository.grepcode.com/java/root/jdk/openjdk/7-b147/sun/nio/fs/UnixException.java#86

According the implementation, when NoSuchFileException is throwed, an ENOENT error occured. ENOENT on unix stands for No such file or directory.

Are you sure file "/home/user/Desktop/indeed.txt" exsits? or you have privileges to access it.

What is the result of command ls -l /home/user/Desktop/indeed.txt

what is the version of jdk you are using?