Passionate Developer Passionate Developer - 4 months ago 23
Java Question

java.lang.ClassCastException: java.util.LinkedHashMap cannot be cast to com.testing.models.Account

I'm getting below error:

java.lang.ClassCastException: java.util.LinkedHashMap cannot be cast to com.testing.models.Account


with below code

final int expectedId = 1;

Test newTest = create();

int expectedResponseCode = Response.SC_OK;

ArrayList<Account> account = given().when().expect().statusCode(expectedResponseCode)
.get("accounts/" + newTest.id() + "/users")
.as(ArrayList.class);
assertThat(account.get(0).getId()).isEqualTo(expectedId);


Is there a reason why I cannot do
get(0)
?

Answer

The issue's coming from Jackson. When it doesn't have enough information on what class to deserialize to, it uses LinkedHashMap.

Since you're not informing Jackson of the element type of your ArrayList, it doesn't know that you want to deserialize into an ArrayList of Accounts. So it falls back to the default.

Instead, you could probably use as(JsonNode.class), and then deal with the ObjectMapper in a richer manner than rest-assured allows. Something like this:

ObjectMapper mapper = new ObjectMapper();

JsonNode accounts = given().when().expect().statusCode(expectedResponseCode)
    .get("accounts/" + newClub.getOwner().getCustId() + "/clubs")
    .as(JsonNode.class);


//Jackson's use of generics here are completely unsafe, but that's another issue
List<Account> accountList = mapper.readValue(
    mapper.treeAsTokens(accounts), 
    new TypeReference<List<Account>>(){}
);

assertThat(accountList.get(0).getId()).isEqualTo(expectedId);