Uploading image using Spring, commons-file upload

I'm trying to upload an image following this and this tutorial but without using maven.

Here is my config related to upload:

ApplicationContext.xml

..
<bean id="multipartResolver"
class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <property name="maxUploadSize" value="10000000">
</property></bean>

My form:

<form:form 
        action="${ contextPath }admin/add-product" 
        method="POST" modelAttribute="addInventoryItemDto"
        enctype="multipart/form-data">
        <table>
        ....
        <tr>
            <td><b>Image:</b></td>
            <td><input type="file" name="image" /></td>
        </tr>
        ....

Controller

@RequestMapping( value = "/add-product", method = RequestMethod.POST )
    public String addProduct( 
    @ModelAttribute( "addInventoryItemDto" ) @Valid AddInventoryItemDto inventoryDto,
    @RequestParam( "image" ) MultipartFile img ) {
        System.out.println("ContentType:" + img.getContentType());
        return "admin/add-product";
    }

I'm getting 404 Bad Request but when I remove the file related stuff in my Controller and form the request is properly sent to my controller

What I'm I missing or did wrong?