title: Jackson ObjectMapper returning null
body: <p>I have the following class:</p>
  
  <pre><code>@JsonRootName(value = "customer")
  @JsonIgnoreProperties(ignoreUnknown = true)
  public class Data{
      @JsonProperty("salutation")
      public String salutation;
      @JsonProperty("firstName")
      public String firstName;
      @JsonProperty("lastName")
      public String lastName;
      @JsonProperty("birthDate")
      public String birthDate;
  }
  </code></pre>
  
  <p>I want to transform an incoming JSON to this POJO. Json look like this:</p>
  
  <pre><code>{   "customer": {
      "lastName": "test lastname",
      "firstName": "test firstname",
      "salutation": "test salutation",
      "birthDate": "test date",
      "addresses": {
        "city": "test city",
        "postalCode": "test postal code",
        "country": "test country",
        "streetNumber": "test number",
        "street": "test street"
      } } }
  </code></pre>
  
  <p>Problem: The actual data is not in the root tag, but nested in <code>"customer"</code>. This is why i used <code>@JsonRootName</code>. Also there is some data like city, postalCode, all in addresses, that I do not need for this object instance. Which is why i added <code>JsonIgnoreProperties(ignoreUnknown = true)</code>.</p>
  
  <p>When I use:</p>
  
  <pre><code>return mapper.readValue(getResource("/test.json"), Data.class);
  </code></pre>
  
  <p>It returns me an instance of Data, but null on every attribute of it. How can I fix this and why doesn't it work? First time using the jackson mapper here.. Thanks!</p>