You need jackson dependency for this serialization and deserialization.

Add this dependency:

Gradle:

compile("com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.9.4")

Maven:

<dependency>
    <groupId>com.fasterxml.jackson.datatype</groupId>
    <artifactId>jackson-datatype-jsr310</artifactId>
</dependency>

After that, You need to tell Jackson ObjectMapper to use JavaTimeModule. To do that, Autowire ObjectMapper in the main class and register JavaTimeModule to it.

import javax.annotation.PostConstruct;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;

@SpringBootApplication
public class MockEmployeeApplication {

  @Autowired
  private ObjectMapper objectMapper;

  public static void main(String[] args) {
    SpringApplication.run(MockEmployeeApplication.class, args);

  }

  @PostConstruct
  public void setUp() {
    objectMapper.registerModule(new JavaTimeModule());
  }
}

After that, Your LocalDate and LocalDateTime should be serialized and deserialized correctly.

Spring Boot 2.2.2 / Gradle:

Gradle (build.gradle):

implementation("com.fasterxml.jackson.datatype:jackson-datatype-jsr310")

Entity (User.class):

LocalDate dateOfBirth;

Code:

ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(new JavaTimeModule());
User user = mapper.readValue(json, User.class);

I had a similar issue which I solved by making two changes

1. Added below entry in application.yaml file

spring:
    jackson:
        serialization.write_dates_as_timestamps: false

2. Add below two annotations to the POJO's LocalDate field

@JsonDeserialize(using = LocalDateDeserializer.class)
@JsonSerialize(using = LocalDateSerializer.class)

Example

import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;

public class Customer   {
    @JsonDeserialize(using = LocalDateDeserializer.class)
    @JsonSerialize(using = LocalDateSerializer.class)
    protected LocalDate birthdate;
}

Eample request format:

{"birthdate": "2019-11-28"}

Example request format as array

{"birthdate":[2019,11,18]}

As it turns out, one should not forget to include jacson dependency into the pom file. This solved the issue for me:

<dependency>
    <groupId>com.fasterxml.jackson.module</groupId>
    <artifactId>jackson-module-parameter-names</artifactId>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.datatype</groupId>
    <artifactId>jackson-datatype-jdk8</artifactId>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.datatype</groupId>
    <artifactId>jackson-datatype-jsr310</artifactId>
</dependency>

Well, what I do on every project is a mix of the options above.

First, add the jsr310 dependency:

<dependency>
    <groupId>com.fasterxml.jackson.datatype</groupId>
    <artifactId>jackson-datatype-jsr310</artifactId>
</dependency>

Important detail: put this dependency on the top of your depedencies list. I already see a project where the Localdate error persists even with this dependency on the pom.xml. But changing the order of the depedency the error was gone.

On your /src/main/resources/application.yml file, setup the write-dates-as-timestamps property:

spring:
  jackson:
    serialization:
      write-dates-as-timestamps: false

And create a ObjectMapper bean as this:

@Configuration
public class WebConfigurer {

    @Bean
    @Primary
    public ObjectMapper objectMapper(Jackson2ObjectMapperBuilder builder) {
        ObjectMapper objectMapper = builder.build();
        objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
        return objectMapper;
    }

}

Following this configuration, the conversion always work on Spring Boot 1.5.x without any error.

Bonus: Spring AMQP Queue configuration

Working with Spring AMQP, pay attention if you have a new instance of Jackson2JsonMessageConverter (common thing when creating a SimpleRabbitListenerContainerFactory). You need to pass the ObjectMapper bean to it, like:

Jackson2JsonMessageConverter converter = new Jackson2JsonMessageConverter(objectMapper);

Otherwise, you will receive the same error.

I have just wrestled with this for 3 hours. I credit the answer from Dherik (Bonus material about AMQP) for bringing me within striking distance of MY answer, YMMV.

I registered the JavaTimeModule in my object mapper in my SpringBootApplication like this:

@Bean
@Primary
public ObjectMapper objectMapper(Jackson2ObjectMapperBuilder builder) {
    ObjectMapper objectMapper = builder.build();
    objectMapper.registerModule(new JavaTimeModule());
    return objectMapper;
}

However my Instants that were coming over the STOMP connection were still not deserialising. Then I realised I had inadvertantly created a MappingJackson2MessageConverter which creates a second ObjectMapper. So I guess the moral of the story is: Are you sure you have adjusted all your ObjectMappers? In my case I replaced the MappingJackson2MessageConverter.objectMapper with the outer version that has the JavaTimeModule registered, and all is well:

@Autowired
ObjectMapper objectMapper;

@Bean
public WebSocketStompClient webSocketStompClient(WebSocketClient webSocketClient,
        StompSessionHandler stompSessionHandler) {
    WebSocketStompClient webSocketStompClient = new WebSocketStompClient(webSocketClient);
    MappingJackson2MessageConverter converter = new MappingJackson2MessageConverter();
    converter.setObjectMapper(objectMapper);
    webSocketStompClient.setMessageConverter(converter);
    webSocketStompClient.connect("http://localhost:8080/myapp", stompSessionHandler);
    return webSocketStompClient;
}

You need to add below code to your pom.xml modules-java8

<!--    Java 8 Date/time    -->
<dependency>
    <groupId>com.fasterxml.jackson.datatype</groupId>
    <artifactId>jackson-datatype-jsr310</artifactId>
</dependency>