Retrofit GSON serialize Date from json string into java.util.date

Retrofit GSON serialize Date from json string into java.util.date

I am using the Retrofit library for my REST calls. Most of what I have
done has been smooth as butter but for some reason I am having issues
converting json timestamp strings into java.util.date objects. The json
that is coming in looks like this.
{
"date": "2013-07-16",
"created_at": "2013-07-16T22:52:36Z",
}
How can I tell Retrofit or GSON to convert these strings into
java.util.date objects?