Spring MVC: jackson-mapper-asl not work with Spring 4

I am trying to convert List of objects into json with the help of jackson-mapper-asl libraries, but in response i got http 406 error. jackson-mapper-asl libraries are on my class path. Following is my Spring MVC controller code:

@RequestMapping(value="/find-sub-categories/{parentId}", method=RequestMethod.GET)
@ResponseBody public List<ProductCategory> findSubCategories(@PathVariable(value="parentId") ProductCategory productCategory) {
    logger.info("In ADMIN findSubCategories Contoller AJAX GET");

    List<ProductCategory> categories = productCategoryService.findAllChildProductCategoriesByParent(productCategory);
    return categories;
}

My Ajax request code:

$.ajax({
            url: url+"/"+parentId,
            type: 'GET',
            success: function(result) {
                var arr = $.parseJSON(result);
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