Spring: RestTemplate returns null object

Assuming you're using Jackson, RestTemplate automatically registers a MappingJackson2HttpMessageConverter which configures the underlying ObjectMapper to ignore unknown properties.

The JSON object has a single attribute named userRegistrations, whereas your Java class has a single attribute named userRegistrationList. They don't match.

They need to match, or you need to add a @JsonProperty annotation of the attribute to make Jackson serialize/parse it as userRegistrations.