org.springframework.hateoas.Resources should serialize content as arrays, not lists.

Jackson is better at serializing arrays than lists since there is no type erasure. When a GET method returns a Resources object, I see something like:

{ 
    "_embedded": {
        "hashMapList": [
            {
                "fld1": "a",
                "_links": {
                    "self": {
                        "href": "http://..."
                    }
                }
            }
        ]
    }
}

The "hashMapList" sticks out. I would rather see this:

{
    "content": [
        {
            "fld1": "a",
            "_links": {
                "self": {
                    "href": "http://..."
                }
            }
        }
    ]
}

In retrospect, Resources.getContents() should have probably returned T[] instead of Collection<T>.

My workaround was to create a class called ArrayResources that extended Resources with the following code:

	@Override
	@JsonIgnore
	public Collection<T> getContent() {
		return super.getContent();
	}
	
	@XmlAnyElement
	@XmlElementWrapper
	@JsonProperty("content")	
	@SuppressWarnings("unchecked")
	public T[] getContentArray() {
		Collection<T> content = getContent();
		return content == null ? null :
			(T[]) content.toArray();
	}

I also had to write ArrayPagedResources that duplicated most of the code in PagedResources. Finally I provided static initializers that I use in my Controller classes right before returning.

ArrayResources.from(Resources)
PagedArrayResources.from(PagedResources)

Not the most elegant solution, but it got me what I want. Ideally, I would like to see the code for Resources changed as shown above. If maintaining backward compatibility is vital, perhaps a mixin similar to ResourcesMixin could provide this as an optional feature. (I tried to do this myself, but I never got it to work.) If a mixin could be developed perhaps an attribute would be appropriate, e.g., @EnableResourcesArraySerialization.

If there is an easier way to accomplish this that I am missing, I welcome suggestions. Kudos for all your great work.

Start by reading Resources, PagedResources, and ResourcesMixin, then reproduce the reported Jackson serialization of Resources content. Decide how array-shaped serialization can be provided without breaking the existing API or requiring duplicated resource classes. Done means the desired JSON is produced and the compatibility behavior is covered.