Pure Java NFSv3 and NFSv4.1 implementation
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kofemann utils: update Cache#cleanUp to use Clock#millis
Use Clock class as time source to run clock based tests.

update Cache#cleanUp to use Clock#millis(). Fix bug in ManualClock
where seconds was used instead of millis. Add test for Cache#cleanUp and

more (and better) tests

Acked-by: Paul Millar
Target: master
Latest commit 4391f3e Nov 16, 2018



The pure java implementation of NFS server version 3, 4.0 and 4.1 including pNFS extension with nfs4.1-files and flex-files layout types.

Building from sources

To build nfs4j from source code Java8 and Maven3 are required.

Implementing own NFS server

public class App {

    public static void main(String[] args) throws Exception {

        // create an instance of a filesystem to be exported
        VirtualFileSystem vfs = new ....;

        // create the RPC service which will handle NFS requests
        OncRpcSvc nfsSvc = new OncRpcSvcBuilder()

        // specify file with export entries
        ExportFile exportFile = new ExportFile(....);

        // create NFS v4.1 server
        NFSServerV41 nfs4 = new NFSServerV41.Builder()
                .withOperationFactory(new MDSOperationFactory())

        // create NFS v3 and mountd servers
        NfsServerV3 nfs3 = new NfsServerV3(exportFile, vfs);
        MountServer mountd = new MountServer(exportFile, vfs);

        // register NFS servers at portmap service
        nfsSvc.register(new OncRpcProgram(100003, 4), nfs4);
        nfsSvc.register(new OncRpcProgram(100003, 3), nfs3);
        nfsSvc.register(new OncRpcProgram(100005, 3), mountd);

        // start RPC service


Use NFS4J in your project


        <name>dCache.ORG maven repository</name>


licensed under LGPLv2 (or later)

How to contribute

NFS4J uses the linux kernel model where git is not only source repository, but also the way to track contributions and copyrights.

Each submitted patch must have a "Signed-off-by" line. Patches without this line will not be accepted.

The sign-off is a simple line at the end of the explanation for the patch, which certifies that you wrote it or otherwise have the right to pass it on as an open-source patch. The rules are pretty simple: if you can certify the below:

    Developer's Certificate of Origin 1.1

    By making a contribution to this project, I certify that:

    (a) The contribution was created in whole or in part by me and I
         have the right to submit it under the open source license
         indicated in the file; or

    (b) The contribution is based upon previous work that, to the best
        of my knowledge, is covered under an appropriate open source
        license and I have the right under that license to submit that
        work with modifications, whether created in whole or in part
        by me, under the same open source license (unless I am
        permitted to submit under a different license), as indicated
        in the file; or

    (c) The contribution was provided directly to me by some other
        person who certified (a), (b) or (c) and I have not modified

    (d) I understand and agree that this project and the contribution
        are public and that a record of the contribution (including all
        personal information I submit with it, including my sign-off) is
        maintained indefinitely and may be redistributed consistent with
        this project or the open source license(s) involved.

then you just add a line saying ( git commit -s )

Signed-off-by: Random J Developer <random@developer.example.org>

using your real name (sorry, no pseudonyms or anonymous contributions.)

Contact Us

For help and development related discussions please contact us: dev (@) dcache (.) org