Convert type="text" Symfony2 to String in Android

I'm working on an android application and on a website using Symfony2. For both, I use a API and I use Retrofit on Android. I have an entity which have a field Column(type="text",nullable=true), but when I get it with Retrofit, it's null (I put it in a String). I cannot have a Column(type="string",nullable=true) because it's an adress and it can be long.

Thanks, and sorry for my english