title: Kotlin - Jackson ignore null values
body: <p>I am getting trouble with parsing JSON with Jackson and I want to ignore null properties. Here is my code.</p>
  
  <pre><code>@JsonIgnoreProperties(ignoreUnknown = true)
  @JsonInclude(JsonInclude.Include.NON_NULL)
  data class ParsedSurvey(
      val items: List&lt;ParsedSurveyItem&gt; = listOf()
  )
  
  @JsonIgnoreProperties(ignoreUnknown = true)
  @JsonInclude(JsonInclude.Include.NON_NULL)
  data class ParsedSurveyItem(
      val type: String = "",
      val text: String = "",
      val instructions: String = "",
      val prog: String = "",
      val `var`: String = "",
      val columns: List&lt;ParsedSurveyAnswer&gt; = listOf(),
      val rows: List&lt;ParsedSurveyAnswer&gt; = listOf(),
      val num: String = "",
      val multi: Boolean = false,
      val random: Boolean = false,
      val min: Int = -1,
      val max: Int = -1,
      val recordOrder: Boolean = false,
      val rowLength: Int = -1
  )
  
  @JsonIgnoreProperties(ignoreUnknown = true)
  @JsonInclude(JsonInclude.Include.NON_NULL)
  data class ParsedSurveyAnswer @JsonCreator(mode = JsonCreator.Mode.PROPERTIES) constructor(
      val text: String = "",
      val prog: String = "&lt;p&gt;&lt;/p&gt;",
      @JsonProperty("isOpen") val isOpen: Boolean = false
  )
  </code></pre>
  
  <p>If I try to set rows property in ParsedSurveyItem to null. I am getting this error: </p>
  
  <pre><code>value failed for JSON property rows due to missing (therefore NULL) value for creator parameter rows which is a non-nullable type.
  Jackson doesn't ignore 
  </code></pre>
  
  <p>Why Jackson parses null values? Thanks for help.</p>