[jcifs] Hundreds of threads while listing directory

[Michael B Allen]

Hi Peter,

Those are name lookup threads. Once upon a time there was something
called WINS and NetBIOS that was used for hostname and "workgroup"
lookups. But it's pretty much non-existant unless you have a really
old network.

Try setting:

  jcifs.resolveOrder = DNS

Name resolution properties are described here:

  http://jcifs.samba.org/src/docs/resolver.html

So by removing WINS and BCAST from the list, I think it should stop
all of the WINS and NetBIOS stuff which stop the code path that is
trying to use threads to lookup names.

Mike

On Thu, Jun 3, 2010 at 5:01 AM, Peter Kossek <pkossek at aristos-online.de> wrote:
> Hello,
>
>
>
> I just started using jCIFS a couple of days before, but now I'm experiencing
> some problems. My application throws an OOME while trying to list the
> content of a directory.
>
>
>
> The exception message:
>
>
>
> Exception in thread "AWT-EventQueue-0" java.lang.OutOfMemoryError: unable to
> create new native thread
>
>         at java.lang.Thread.start0(Native Method)
>
>         at java.lang.Thread.start(Thread.java:597)
>
>         at jcifs.UniAddress.lookupServerOrWorkgroup(UniAddress.java:173)
>
>         at jcifs.UniAddress.getAllByName(UniAddress.java:290)
>
>         at jcifs.UniAddress.getByName(UniAddress.java:245)
>
>         at jcifs.smb.Dfs.getTrustedDomains(Dfs.java:62)
>
>         at jcifs.smb.Dfs.resolve(Dfs.java:167)
>
>         at jcifs.smb.SmbFile.resolveDfs(SmbFile.java:666)
>
>         at jcifs.smb.SmbFile.send(SmbFile.java:768)
>
>         at jcifs.smb.SmbFile.doFindFirstNext(SmbFile.java:2023)
>
>         at jcifs.smb.SmbFile.doEnum(SmbFile.java:1731)
>
>         at jcifs.smb.SmbFile.listFiles(SmbFile.java:1708)
>
>         at jcifs.smb.SmbFile.listFiles(SmbFile.java:1641)
>
>         at as_file.as_smb_lister.findFile(as_smb_lister.java:140)
>
>         ...
>
>
>
> The code for finding the file:
>
>
>
> public static SmbFile[] findFile(SmbFile startFolder, String filename) {
>
>         ArrayList<SmbFile> files = new ArrayList<SmbFile>();
>
>         ArrayList<SmbFile> foldersToWalk = new ArrayList<SmbFile>();
>
>
>
>         try {
>
>             if (startFolder.isDirectory()) {
>
>                 foldersToWalk.add(startFolder);
>
>             }
>
>             while (foldersToWalk.size() > 0) {
>
>                 SmbFile lookInto = foldersToWalk.remove(0);
>
>                 System.out.println("walking " + lookInto.getPath());
>
>                 try {
>
>                     SmbFile[] found = lookInto.listFiles(); // line 140
>
>                     for (int i = 0; i < found.length; i++) {
>
>                         if (found[i].getName().endsWith("/")) {
>
>                             foldersToWalk.add(found[i]);
>
>                         } else {
>
>                             if (found[i].getName().equals(filename)) {
>
>                                 files.add(found[i]);
>
>                             }
>
>                         }
>
>                     }
>
>                 } catch (SmbException ex) {
>
>                     System.out.println(ex.getMessage());
>
>                 }
>
>             }
>
>         } catch (SmbException ex) {
>
>             System.out.println(ex.getMessage());
>
>         }
>
>         SmbFile[] result = new SmbFile[files.size()];
>
>         for (int i = 0; i < files.size(); i++) {
>
>             result[i] = files.get(i);
>
>         }
>
>
>
>         SmbFile[] found = new SmbFile[files.size()];
>
>         for (int i = 0; i < files.size(); i++) {
>
>             found[i] = files.get(i);
>
>         }
>
>         return found;
>
>     }
>
>
>
>
>
>
>
> The directory it's trying to list is smb://KOSSEK/C$/Windows/winsxs/Backup/
> which is known to contain lots of files, 3256 files in this case.
>
> I noticed that there is a peak of numbers of threads, up to more than 2000
> threads (QueryThreads) at once that seem to bring the VM to its limits.
> Maybe I made a mistake in my code that forces this massive creation of
> threads, but I just can't find it. What can I do to fix this?
>
>
>
> Thanks in advance for your help.
>
>
>
> Best regards - Peter



-- 
Michael B Allen
Java Active Directory Integration
http://www.ioplex.com/