title: Jackson ObjectMapper readValue() unrecognized field when parsing to Object
body: <p>I am creating simple rest client in Java/Spring. My request has been consumed properly by remote service and I got the response <strong>String</strong> something:</p>
  
  <pre><code>{"access_token":"d1c9ae1b-bf21-4b87-89be-262f6","token_type":"bearer","expires_in":43199,"grant_type":"client_credentials"}
  </code></pre>
  
  <hr>
  
  <p>The code below is the Object where I want to bind values from Json Response</p>
  
  <pre><code>package Zadanie2.Zadanie2;
  
  import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
  import com.fasterxml.jackson.annotation.JsonProperty;
  
   public class Token {
  String access_token;        
  String token_type;
  int expiresIn;
  String grantType;
  //////////////////////////////////////////////////////
  public Token() {
      /////////////////////////////////
  }
  /////////////////////////////////////////////////////
  
  public void setAccessToken(String access_token) {
      this.access_token=access_token;
  }
  public String getAccessToken() {
      return access_token;
  }
  ////////////////////////////////////////////////
  public void setTokenType(String token_type) {
      this.token_type=token_type;
  }
  public String getTokenType() {
      return token_type;
  }
  //////////////////////////////////////////////////////
  public void setExpiresIn(int expiresIn) {
      this.expiresIn=expiresIn;
  }
  public int getExpiresIn() {
      return expiresIn;
  }
  //////////////////////////////////////////////////////////
  public void setGrantType(String grantType) {
      this.grantType=grantType;
  }
  public String getGrantType() {
      return grantType;
  }
  }
  </code></pre>
  
  <p>all the time I am getting "unrecognized field access_token" but when I add <code>objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);</code> 
   then access_token will be null</p>
  
  <pre><code>        jsonAnswer=template.postForObject(baseUriAuthorize, requestEntity,  String.class);  
          System.out.println(jsonAnswer);
          Token token=objectMapper.readValue(jsonAnswer, Token.class);
          System.out.println(token.getAccessToken());
  </code></pre>
  
  <p>I tried with <code>@JsonProperty</code> annotations. I tried with changing field by for example <code>"@JsonProperty(accessToken)"</code> because I thought there is an issue with "_" sign in variable name. I added getters and setters. Maybe there is a problem with the version I use but I don't think so because I am using <code>"com.fasterxml.jackson.core"</code></p>