Java 8 date/time type `java.time.Instant` not supported by default:

Learn about fixing the error "Java 8 date/time type `java.time.Instant` not supported by default" when serializing and deserializing Java 8 date-time classes using Jackson.

1. Questions

Errors occur when we serialize Java objects or deserialize JSON into POJOs, and POJOs contain new Java 8 datetime classes like LocalDate, LocalTime, LocalDateTime, etc.

For example, the Employee class below has a field of type LocalDate.

public class Employee {

  private Long id;
  private String name;
  private LocalDate dateOfBirth;
}

When we serialize an instance of this class, we get the following exception:

Exception in thread "main" java.lang.IllegalArgumentException: Java 8 date/time type `java.time.LocalDate` not supported by default: add Module "com.fasterxml.jackson.datatype:jackson-datatype-jsr310" to enable handling (through reference chain: com.howtodoinjava.core.objectToMap.Employee["dateOfBirth"])
	at com.fasterxml.jackson.databind.ObjectMapper ._convert(ObjectMapper.java:4393)
	at com.fasterxml.jackson.databind.ObjectMapper .convertValue(ObjectMapper.java:4324)
	at com.howtodoinjava.core.objectToMap .ObjectToMapUsingJackson.main(ObjectToMapUsingJackson.java:25)

An example of exception,

When you visit the /actuator/info node, you will find the following error page

This page contains the following errors:

error on line 1 at column 1: Document is empty

Below is a rendering of the page up to the first error.

2. Solutions

We had to add support for new Java 8 classes in two steps to fix this bug.

First, add the latest version of the com.fasterxml.jackson.datatype:jackson-datatype-jsr310 Maven dependency.

pom.xml

<dependency>
  <groupId>com.fasterxml.jackson.datatype</groupId>
  <artifactId>jackson-datatype-jsr310</artifactId>
  <version>2.13.4</version>
</dependency>

Second, depending on what you use, register the module JavaTimeModule with ObjectMapper or JsonMapper.

ObjectMapper objectMapper = new ObjectMapper();
objectMapper.registerModule(new JavaTimeModule());

//or 

JsonMapper jsonMapper = new JsonMapper();
jsonMapper.registerModule(new JavaTimeModule());