//Exception
2018-02-23 13:29:09.046 ERROR 24730 --- [nio-9300-exec-1] o.a.c.c.C.[.[.[.[dispatcherServlet]      : Servlet.service() for servlet [dispatcherServlet] in context with path [/services] threw exception [Request processing failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [*.model.User]: Constructor threw exception; nested exception is java.lang.IllegalArgumentException: Parameter specified as non-null is null: method *.model.User.<init>, parameter name] with root cause
java.lang.IllegalArgumentException: Parameter specified as non-null is null: method *.User.<init>, parameter name

//JSON
{
    "name": "name",
    "surname": "surname",
    "email": "email",
    "password": "pswd"
}

//Model
@Entity
@Table
data class User(
        @Id
        @GeneratedValue(strategy = GenerationType.AUTO)
        var userId: Long?,
        var name: String,
        var surname: String,
        var email: String,
        var password: String,
        (...)
        ): Resource() {
        (...)
}

@Configuration
class JacksonConfig {
    @Bean
    fun mappingJackson2HttpMessageConverter(): MappingJackson2HttpMessageConverter {
        val mapper = ObjectMapper().registerKotlinModule()
        mapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false)
        var user = mapper.readValue<User>("{n" +
                "t"name": "name",n" +
                "t"surname": "surname",n" +
                "t"email": "email",n" +
                "t"password": "pswd"n" +
                "}")
        return MappingJackson2HttpMessageConverter(mapper)
    }
}

<dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-core</artifactId>
        <version>${jackson.version}</version> <!--2.9.4-->
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-annotations</artifactId>
        <version>${jackson.version}</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>${jackson.version}</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.module</groupId>
        <artifactId>jackson-module-kotlin</artifactId>
        <version>${jackson.version}</version>
    </dependency>