Stripe PaymentSource not expanding after upgrading to newest version of Java library

I'm trying to get the payment methods attached to a given Customer. I recently upgraded to version 2020.19.0 of the Stripe Java library and I'm following the example they've put forward.

The problem is that the Java library doesn't seem to recognize that the PaymentSource object has any parameters:

Map<String, Object> params = Maps.newHashMap();
params.put("object", "card");
params.put("limit", 100);

// Get the credit cards
List<PaymentSource> cards =
  customer.getSources().list(params).getData();

for (PaymentSource c : cards) {
  c.getObject();    // not recognized in IDE
}

Anyone else run into this?

stripe-java is pinned to a specific API version. When you upgrade to a new major version in the library it usually contains breaking changes and/or an upgrade to the most recent API version. This is what happened in 20.0.0 as documented here where the library was pinned to 2020-08-27.

That new API version has a lot of changes including some cleanup on the Customer resource. Stripe stopped returning sub-lists by default: subscription, tax_ids and sources are not returned unless you explicitly expand those sub-lists directly. This allows the API to be faster in most cases and to selectively select the sub-lists you need in specific parts of your code.

In Java, this means that you need to expand the sources collection if you want to be able to create/attach a new card. This is also documented in the API reference here and the code looks like this:

List<String> expandList = new ArrayList<>();
expandList.add("sources");

Map<String, Object> retrieveParams = new HashMap<>();
retrieveParams.put("expand", expandList);

Customer customer = Customer.retrieve(
  "cus_IEB3RFCf76Fais",
  retrieveParams,
  null
);

Map<String, Object> params = new HashMap<>();
params.put("object", "card");
params.put("limit", 3);

PaymentSourceCollection cards = customer.getSources().list(params);