Intermittent FileNotFoundException exception when writing files

Question

OS: Windows
JRE 1.3.1
I have an application that tries to write files to an existing folder (overwriting the files that are already there). This code is run very often at my site, and I�ve never had a problem. At some customer sites, we get an intermittent exception:
java.io.FileNotFoundException (Cannot create a file when that file already exists).
Each time it is run and the exception occurs, a different file takes the hit. Sometimes running against one folder works and against another doesn�t, on the same machine. I don�t think file protections are an issue (if I try to reproduce the problem by marking a file to be written over as read-only, I get an �access denied� exception on that file consistently).
Of course, it is intermittent at just a few sites, and I can�t reproduce it myself.
I�m wondering if it is possible that some other process (say a virus scan or back-up utility) is temporarily locking files in a way such that when I do my FileOutputStream.write() I catch this exception. Has anyone seen or heard of anything like this?
Thanks,
Paul

Answer 1

Are you sure you are not accidently trying to open an output stream on a directory? From the API docs:
FileOutputStream
public FileOutputStream(File file)
                 throws FileNotFoundExceptionCreates a file output stream to write to the file represented by the specified File object. A new FileDescriptor object is created to represent this file connection.
First, if there is a security manager, its checkWrite method is called with the path represented by the file argument as its argument.
If the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason then a FileNotFoundException is thrown.
Parameters:
file - the file to be opened for writing.
Throws:
FileNotFoundException - if the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason
SecurityException - if a security manager exists and its checkWrite method denies write access to the file.
See Also:
File.getPath(), SecurityException, SecurityManager.checkWrite(java.lang.String)Note the case where a FileNotFoundException will be thrown.
- Saish