How to parse JSON in rest assured stepdefination class?

Question

Below is the JSON request body: { "memberId":"21bda54e-895a-4528-8788-698fce5b5", "prodList":[ { "productCode":"312" } ] }

Below is the code which I have written. Let me know How to parse the above JSON payload in the rest assured step definition file.

public class Generate_Bill {

private Response response;
private String accessToken;
private void jsonBodyUsingMap(String string, List singletonList) {
    // TODO Auto-generated method stub
    
}
public String generateStringFromResource(String path) throws Throwable {

    return new String(Files.readAllBytes(Paths.get(path)));

}

@Given("Post Generate Bill API")
public void post_Generate_Bill_API() {
    RestAssured.baseURI = Initialization.url;
}

@When("call the Post Generate Bill API with valid token and details")
public void call_the_Post_Generate_Bill_API_with_valid_token_and_details() throws Throwable {

    accessToken = TokenGeneration.accessToken;
    String jsonBody = generateStringFromResource("src/test/java/request/Generate_Bill.json");

    //Gson gson = new Gson();
    //JsonObject inputObj  = gson.fromJson(jsonBody, JsonObject.class);

    Map<String, Object> jsonBodyUsingMap = new HashMap<String, Object>();
    
    // singletonList() to return an immutable list containing only the specified object
    jsonBodyUsingMap("prodList", Collections.singletonList(new HashMap<String, Object>() {
    {
        put("productCode", "31");
    }}
    ));
    
        jsonBodyUsingMap.put("memberId", "21bda54e-895a-4528-8788-6985f6fce5b5");
    

response = RestAssured.given()
        .header("Content-Type", "application/json")
        .header("Authorization", "Bearer " + accessToken)
        .when()
        .post(Initialization.Generate_Bill);    

}


@Then("validate Generate Bill API for {int} status code")
public void validate_Generate_Bill_API_for_status_code(Integer int1) {
    int status_code = response.getStatusCode();
    System.out.println("status is: " +status_code);
    Assert.assertEquals(200, status_code);
}

}