Below is reference code : from http://doc.nuxeo.com/display/NXDOC/Using+Nuxeo+Automation+Client

   // Get The Root
    Document root = (Document) session.newRequest("Document.Fetch").set(
            "value", "/").execute();
    // Create a File Document
    session.newRequest("Document.Create").setInput(root).set("type", "File").set(
            "name", "myfile").set("properties", "dc:title=My File").execute();

    // Upload The file
    File file = getTheFileToUpload();
    FileBlob fb = new FileBlob(file);
    fb.setMimeType("text/xml");
    // uploading a file will return null since we used HEADER_NX_VOIDOP
    session.newRequest("Blob.Attach").setHeader(
            Constants.HEADER_NX_VOIDOP, "true").setInput(fb)
            .set("document", "/myfile").execute();

File content not creating in Nuxeo server Error message:“Binary request not supported”