uploader + servlet

Hi!
I’m new in webix. I want to upload file with uploader.

            { view:   "uploader",
              id:     "uploader_1",
              multiple: false,
              value:  "Загрузить модель...",
              link:   "mylist",
              upload: "modelupload",
            },
            {
              view: "list",  
              id:   "mylist", 
              type: "uploader",
              autoheight: true, 
              borderless: true    
            }

On server side a use servlet modelupload.

@WebServlet("/modelupload")
@MultipartConfig
public class ModelUpload extends HttpServlet { .... }

After pressing button and selecting file I see yellow exclamation triangle. Nothing is loading. When I use

<form action="modelupload" method="post" enctype="multipart/form-data">
    <input type="text" name="description" />
    <input type="file" name="file" />
    <input type="submit" />
</form> 

file was loaded.
How can I use webix with servlet? What is incorrect in me code?

I found & correct errors in my “green” code. Now everything is fine. Question is no more actual.