title: DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES is not getting set to false in spring boot 1.3
body: <p>I have configured <code>@Bean</code> for <code>Jackson2ObjectMapperBuilder</code> where I am setting the <code>DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES</code> property set to <code>false</code>, in order to allow deserialization of JSON objects with unmapped properties. As-</p>
  
  <pre><code>@Bean
  public Jackson2ObjectMapperBuilder filteringObjectMapperBuilder() {
      Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder();
      builder.failOnUnknownProperties(false);
      builder.serializationInclusion(Include.NON_EMPTY);
      builder.annotationIntrospector(new DefaultFilterAnnotationIntrospector("DynamicFieldFilter"));
      return builder;
  }
  </code></pre>
  
  <p>As per spring boot reference documentation Defining a <code>@Bean</code> of type <code>Jackson2ObjectMapperBuilder</code> will allow you to customize both default <code>ObjectMapper</code> and <code>XmlMapper</code> (used in <code>MappingJackson2HttpMessageConverter</code> and <code>MappingJackson2XmlHttpMessageConverter</code> respectively).</p>
  
  <p>But <code>Jackson2ObjectMapperBuilder</code> created in our <code>@Bean</code> configuration class, is not getting used in the message converters. and when a incoming request has unknown properties , it is getting failed. </p>
  
  <p>But When I am configuring Object Mappers as </p>
  
  <pre><code>@Bean
  public Jackson2ObjectMapperBuilder filteringObjectMapperBuilder() {
      Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder();
      builder.failOnUnknownProperties(false);
      builder.serializationInclusion(Include.NON_EMPTY);
      builder.annotationIntrospector(new DefaultFilterAnnotationIntrospector("DynamicFieldFilter"));
      return builder;
  }
  @Bean
  public MappingJackson2HttpMessageConverter jacksonMessageConverter(Jackson2ObjectMapperBuilder builder) {
      return new MappingJackson2HttpMessageConverter(builder.build());
  }
  
  @Bean
  @ConditionalOnClass(
      name = {"com.fasterxml.jackson.dataformat.xml.XmlMapper"}
  )
  public MappingJackson2XmlHttpMessageConverter jacksonXmlMessageConverter(Jackson2ObjectMapperBuilder builder) {
      return new MappingJackson2XmlHttpMessageConverter(builder.createXmlMapper(true).build());
  }
  </code></pre>
  
  <p>It is able to accept that incoming request and is not getting failed with unknown properties.</p>
  
  <p>But as per spring boot reference documentation these are not required to configure. Can someone suggest why this is occurring with Spring boot 1.3?</p>