Deserializing to a templated class with different possible parameterized types

Question

I have a class with nested subclasses

public class OuterClass {
    class GenericClassHolder<R> {
        @SerializedName("results")
        List<R> results;

        public GenericClassHolder() {}

        public List<R> getResults() {
            return results;
        }
    }

    class ExampleClassA {
        @SerializedName("A")
        int a;

        public ExampleClassA() {}

        public int getA() {return a;}
    }


    class ExampleClassB {
        @SerializedName("B")
        String b;

        public ExampleClassA() {}

        public String getB() {return b;}
    }
}

And I would like to deserialize to different versions of GenericClassHolder in different circumstances. Currently I have

public <T> OuterClass.GenericClassHolder<T> parseJson(final String responseStr, final Class<T> responseClass) throws JsonSyntaxException {
    return Gsons.getInstance().fromJson(responseStr, new TypeToken<OuterClass.GenericClassHolder<T>>() {
    }.getType());
}


String jsonString = "{results:[{A:4}]}";
OuterClass.GenericClassHolder<OuterClass.ExampleClassA> ex = parseApiResponse(jsonString, OuterClass.ExampleClassA.class);

which seems to not break anything but when I get to the following line

System.out.println("I read the string and parsed it! A: " + ex.getResults().get(0).getA());

I get the error

Exception in thread "main" java.lang.ClassCastException: com.google.gson.internal.LinkedTreeMap cannot be cast to OuterClass$ExampleClassA

How can I achieve the goal of being able to parse to a templated class that contains a list of the parameterized type?

-I am using Java 7.