Gson TypeToken with dynamic ArrayList item type

Question

I have this code:

Type typeOfObjectsList = new TypeToken>() {}.getType();
List objectsList = new Gson().fromJso         


        

Answer 1

Option 1 - implement java.lang.reflect.ParameterizedType yourself and pass it to Gson.

private static class ListParameterizedType implements ParameterizedType {

    private Type type;

    private ListParameterizedType(Type type) {
        this.type = type;
    }

    @Override
    public Type[] getActualTypeArguments() {
        return new Type[] {type};
    }

    @Override
    public Type getRawType() {
        return ArrayList.class;
    }

    @Override
    public Type getOwnerType() {
        return null;
    }

    // implement equals method too! (as per javadoc)
}

Then simply:

Type type = new ListParameterizedType(clazz);
List list = gson.fromJson(json, type);

Note that as per javadoc, equals method should also be implemented.

Option 2 - (don't do this) reuse gson internal...

This will work too, at least with Gson 2.2.4.

Type type = com.google.gson.internal.$Gson$Types.newParameterizedTypeWithOwner(null, ArrayList.class, clazz);