Additional attributes not working - magento

Question

I am trying to add the following 2 additional attributes through API. I am not getting any error, however it is not getting uploaded. It would be great if some one could give me a suggestion.
catalogProductAdditionalAttributesEntity AdAtrributeEntity = new catalogProductAdditionalAttributesEntity();
associativeEntity[] AdditionalAttributes = new associativeEntity[2];
associativeEntity AdditionalAttributeOne = new associativeEntity();
associativeEntity AdditionalAttributeTwo = new associativeEntity();
AdditionalAttributeOne.key = "color";
AdditionalAttributeOne.value = "green";
AdditionalAttributeTwo.key = "size";
AdditionalAttributeTwo.value = "xl";
AdditionalAttributes[0] = AdditionalAttributeOne;
AdditionalAttributes[1] = AdditionalAttributeTwo;
AdAtrributeEntity.single_data = AdditionalAttributes;
ProductEntity.additional_attributes = AdAtrributeEntity;
MyService.catalogProductUpdate(Mylogin, SKU, ProductEntity, null, null)

Answer 1

I know this is older, but I found a solution. 'single_data' and 'multi_data' need to have an array inside it that has the arrays of attributes.
product_data = {
'name' => self.get_attribute_value('name'),
'description' => self.get_attribute_value('description'),
'short_description' => self.get_attribute_value('short_description'),
'weight' => self.get_attribute_value('weight'),
'status' => self.get_attribute_value('status'),
'categories' => compose_categories,
'url_key' => self.get_attribute_value('url_key'),
'price' => self.get_attribute_value('price'),
'additional_attributes' => { 'single_data' => { items: compose_attribute_values }}
}
In the example, I named the additional array 'item', hoever, you can call it whatever you want. I used 'item' because the API returns many values like that. The additional attributes look something like this in PHP:
...
'additional_attributes' = array(
'single_data' => array(
'item' => array(
[0] => array(
'key' => 'some_attribute_code',
'value' => 'some_attribute_value'
)
[1] => array(
'key' => 'some_other_attribute_code',
'value' => 'some_other_attribute_value'
)
)
)
)
...

Answer 2

This work for add additional_attributes:
'additional_attributes' => array(
'single_data' => array(
array(
'key' =>'manufacturer',
'value' => '10'
)
)
)

Answer 3

Example for Java (Apache XML-RPC client + Gson):
I have attribute manufacturer with option: Adidas (ID: 318)
Product entity:
...
#SerializedName("additional_attributes")
private Map<String,Map<String,String>> additionalAttributes;
...
// getters + setters
...
code:
...
Map<String,String> attribute = new HashMap<>();
attribute.put("manufacturer", "318");
Map<String,Map<String,String>> additionalAttributes = new HashMap<>();
additionalAttributes.put("single_data", attribute);
product.setAdditionalAttributes(additionalAttributes);
...
then do product.update api request
p.s: of course it's a little bit weird, but you can wrap that with some facade