GSON converts to LinkedHashMap instead of my object

I have this snippet of code:

public abstract class Repository<Entity extends BaseObject> {

...

public void readFromJson(){
    String content = "JSON content here";
    Gson gson = new Gson();
    Type entityType = new TypeToken<JSONObject<Entity>>(){}.getType();

    jsonObject = gson.fromJson(content, entityType);

    for (Entity ent : jsonObject.getEntities()) ;
    }
}

When I try to do the foreach my entities object is no longer of type Entity but LinkedHashMap and I get this exception: java.lang.ClassCastException: java.util.LinkedHashMap cannot be cast to com.tranca.bookstore.domain.shared.BaseObject

Here is the JSONObject class(created by me)

public class JSONObject<Entity> {

private List<Entity> entities = new ArrayList<Entity>();
private long lastId = -1;
public List<Entity> getEntities() {
    return entities;
}
public void setEntities(List<Entity> entities) {
    this.entities = entities;
}
public long getLastId() {
    return lastId;
}
public void setLastId(long lastId) {
    this.lastId = lastId;
}

public void incrementLastId() {
    this.lastId++;
}

}

maybe the base object is relevant so I will put the code here:

public abstract class BaseObject implements Serializable {

protected long id = (long) -1;
protected int version = 0;

protected BaseObject(){}

public long getId() {
    return id;
}
public void setId(long id) {
    this.id = id;
}
public int getVersion() {
    return version;
}
public void setVersion(int version) {
    this.version = version;
}

}