Where is the file descriptor leak in this code?

Question

The following "appendStringToFile" method is used to append a String to a file. My java app calls this method a few times per minute, and then crashes after running for about 12 hours. The exception is "Too many open files". The code that calls it does so from a synchronized block, so concurrency is not the problem, and it would seem that only one file descriptor should be used at a time.
Can anyone find the problem?
     public static void createParentDirectoryIfNeeded(String path) {
          String dirPath = path.substring(0, path.lastIndexOf('/'));
          File dir = new File(dirPath);
          if (!dir.exists()) {
               dir.mkdirs();
     public static void appendStringToFile(String s, String path) {
          FileWriter fileWriter = null;
          try {
               createParentDirectoryIfNeeded(path);
               // create file if it doesn't already exist
               File file = new File(path);
               file.createNewFile();
               if (s != null) {
                    fileWriter = new FileWriter(file, true);
                    fileWriter.write(s.toCharArray());
          } catch (IOException ioe) {
               ErrorHandler.handleError(ioe, LOG);
          } finally {
               if (fileWriter != null) {
                    try {
                         fileWriter.close();
                    } catch (IOException ioe) {
                         ErrorHandler.handleError(ioe, LOG);
     }Edited by: mikewertheim on Sep 26, 2008 11:54 AM
Edited by: mikewertheim on Sep 26, 2008 11:54 AM
Edited by: mikewertheim on Sep 26, 2008 11:55 AM
Edited by: mikewertheim on Sep 26, 2008 11:56 AM

Answer 1

I don't know what is causing your problem but I can suggest several improvements.
1) Given a file 'f' then one can create the parent directory using   f.getParentFile().mkdirs();so that one does not need to useString dirPath = path.substring(0, path.lastIndexOf('/'));          2) There is not need to test if the directory exists before creating it. If it exists then   f.getParentFile().mkdirs(); will just do nothing.
3) There is no need to usefile.createNewFile();because if the file does not exist then fileWriter = new FileWriter(file, true);will create it.