and many thanks for your help in advance! I am trying to set up a simple Spring + Redis project, using IntelliJ, and sadly it just doesn't work.

I have checked countless forum posts here, but sadly to no avail. Whilst many of them are somewhat related, they are not the same, and I was unable to use the insights provided to my particular situation.

For convenient reproduction of the issue, I am listing every step of what I did below:

Project Setup

1. Start IntelliJ IDEA 2023.1.4 (Ultimate Edition)
2. File -> New -> Project... ->Spring Initializr
3. Language: Java
4. Type: Gradle - Kotlin
5. Click Next
6. Spring Boot: 3.1.4
7. Select: Lombok+Spring Web+Spring Data Redis (Access+Driver)

Application properties

8. I added the following to application.properties in src/main/resources:

spring.data.redis.host=localhostspring.data.redis.port=6379

(Note that Redis is running locally in a container and I tested that it works fine / is reachable on port 6379)

Custom data class

9. Right-click main package (in my case com.example.demo), and click New -> Java Class
10. Name the class MyObject and add the following:

package com.example.demo;import lombok.Data;import java.time.Instant;@Datapublic class MyObject {    Instant timestamp;    String textPayload;}

Configuration class

11. Right-click main package (in my case com.example.demo), and click New -> Java Class
12. Name the class AppConfig and add the following code:

package com.example.demo;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.data.redis.connection.RedisConnectionFactory;import org.springframework.data.redis.core.RedisTemplate;import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer;import org.springframework.data.redis.serializer.StringRedisSerializer;@Configurationpublic class AppConfig {    @Bean    public RedisTemplate<String, MyObject> redisTemplate(RedisConnectionFactory factory) {        RedisTemplate<String, MyObject> template = new RedisTemplate<>();        template.setConnectionFactory(factory);        // Serialization for keys. By default, it uses JdkSerializationRedisSerializer        template.setKeySerializer(new StringRedisSerializer());        // Serialization for values. By default, it uses JdkSerializationRedisSerializer        // Here, we use Jackson to convert MyObject to JSON        template.setValueSerializer(new GenericJackson2JsonRedisSerializer());        return template;    }}

Create controller

13. Right-click main package (in my case com.example.demo), and click New -> Java Class
14. Name the class MyController and add the following code:

package com.example.demo;import lombok.AccessLevel;import lombok.RequiredArgsConstructor;import lombok.experimental.FieldDefaults;import org.springframework.data.redis.core.RedisTemplate;import org.springframework.http.ResponseEntity;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.RestController;import java.time.Instant;@FieldDefaults(makeFinal = true, level = AccessLevel.PRIVATE)@RequiredArgsConstructor@RestControllerpublic class MyController {    RedisTemplate<String, MyObject> redisTemplate;    @GetMapping("/save")    public ResponseEntity<String> saveObject() {        MyObject myObject = new MyObject();        myObject.setTimestamp(Instant.now());        myObject.setTextPayload("some data");        redisTemplate.opsForValue().set("myObject", myObject);        return ResponseEntity.ok("Object saved");    }    @GetMapping("/read")    public ResponseEntity<MyObject> readObject() {        return ResponseEntity.ok(redisTemplate.opsForValue().get("myObject"));    }}

Result

The above will then lead to the following exception when trying to call the `/save/ endpoint:

com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Java 8 date/time type `java.time.Instant` not supported by default: add Module "com.fasterxml.jackson.datatype:jackson-datatype-jsr310" to enable handling (through reference chain: com.example.demo.MyObject["timestamp"])    at com.fasterxml.jackson.databind.exc.InvalidDefinitionException.from(InvalidDefinitionException.java:77) ~[jackson-databind-2.15.2.jar:2.15.2]    at com.fasterxml.jackson.databind.SerializerProvider.reportBadDefinition(SerializerProvider.java:1308) ~[jackson-databind-2.15.2.jar:2.15.2]    at com.fasterxml.jackson.databind.ser.impl.UnsupportedTypeSerializer.serialize(UnsupportedTypeSerializer.java:35) ~[jackson-databind-2.15.2.jar:2.15.2]    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:732) ~[jackson-databind-2.15.2.jar:2.15.2]    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:772) ~[jackson-databind-2.15.2.jar:2.15.2]    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeWithType(BeanSerializerBase.java:655) ~[jackson-databind-2.15.2.jar:2.15.2]    at com.fasterxml.jackson.databind.ser.impl.TypeWrappedSerializer.serialize(TypeWrappedSerializer.java:32) ~[jackson-databind-2.15.2.jar:2.15.2]    at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider._serialize(DefaultSerializerProvider.java:479) ~[jackson-databind-2.15.2.jar:2.15.2]    at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:318) ~[jackson-databind-2.15.2.jar:2.15.2]    at com.fasterxml.jackson.databind.ObjectMapper._writeValueAndClose(ObjectMapper.java:4719) ~[jackson-databind-2.15.2.jar:2.15.2]    at com.fasterxml.jackson.databind.ObjectMapper.writeValueAsBytes(ObjectMapper.java:3987) ~[jackson-databind-2.15.2.jar:2.15.2]    at org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer.serialize(GenericJackson2JsonRedisSerializer.java:220) ~[spring-data-redis-3.1.4.jar:3.1.4]    at org.springframework.data.redis.core.AbstractOperations.rawValue(AbstractOperations.java:128) ~[spring-data-redis-3.1.4.jar:3.1.4]    at org.springframework.data.redis.core.DefaultValueOperations.set(DefaultValueOperations.java:236) ~[spring-data-redis-3.1.4.jar:3.1.4]    at com.example.demo.MyController.saveObject(MyController.java:24) ~[main/:na]    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[na:na]    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]    at java.base/java.lang.reflect.Method.invoke(Method.java:568) ~[na:na]    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-6.0.12.jar:6.0.12]    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150) ~[spring-web-6.0.12.jar:6.0.12]    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:118) ~[spring-webmvc-6.0.12.jar:6.0.12]    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:884) ~[spring-webmvc-6.0.12.jar:6.0.12]    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797) ~[spring-webmvc-6.0.12.jar:6.0.12]    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-6.0.12.jar:6.0.12]    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1081) ~[spring-webmvc-6.0.12.jar:6.0.12]    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:974) ~[spring-webmvc-6.0.12.jar:6.0.12]    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1011) ~[spring-webmvc-6.0.12.jar:6.0.12]    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:903) ~[spring-webmvc-6.0.12.jar:6.0.12]    at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:564) ~[tomcat-embed-core-10.1.13.jar:6.0]    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:885) ~[spring-webmvc-6.0.12.jar:6.0.12]    at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658) ~[tomcat-embed-core-10.1.13.jar:6.0]    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:205) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51) ~[tomcat-embed-websocket-10.1.13.jar:10.1.13]    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-6.0.12.jar:6.0.12]    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116) ~[spring-web-6.0.12.jar:6.0.12]    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-6.0.12.jar:6.0.12]    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116) ~[spring-web-6.0.12.jar:6.0.12]    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-6.0.12.jar:6.0.12]    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116) ~[spring-web-6.0.12.jar:6.0.12]    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:174) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:149) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:167) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:482) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:115) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:341) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:391) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:894) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1740) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-10.1.13.jar:10.1.13]    at java.base/java.lang.Thread.run(Thread.java:833) ~[na:na]

Solution approach #1

My first attempt was to follow the advice given in the exception message: "com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Java 8 date/time type java.time.Instant not supported by default: add Module "com.fasterxml.jackson.datatype:jackson-datatype-jsr310" to enable handling (through reference chain: com.example.demo.MyObject["timestamp"])"

So I added the following line to my build.gradle.kts file:

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

...and hit the Gradle reload button / press Ctrl + Shift + O in IntelliJ

Result: the same exception as above.

Solution approach #2

Keeping the newly added dependency in there for good measure, I attempted several other solution approaches suggested here on Stack Overflow.

Add a bean for the ObjectMapper singleton in my configuration

Source: Spring Boot 2.5.0 and InvalidDefinitionException: Java 8 date/time type java.time.Instant not supported by default

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

Result: same exception as above.

Solution approach #3

Another variant for an ObjectMapper singleton

Source: How do I enable the JSR310 support for LocalDate using Jackson?

    @Bean    public ObjectMapper objectMapper() {        return JsonMapper.builder()                         .addModule(new JavaTimeModule())                         .build();    }

Result: same exception as above.

Solution approach #4

Specify bean for Jackson2ObjectMapperBuilder

Source: ChatGPT's suggestion

    @Bean    public Jackson2ObjectMapperBuilder jackson2ObjectMapperBuilder() {        return new Jackson2ObjectMapperBuilder().modules(new JavaTimeModule());    }

Result: same exception as above.

Help?

I tried many other things, spending quite some time on this problem, but nothing would work. Can it really be that hard to serialize Instant's with Spring/Redis? What am I missing? Can someone help?

Thank you so much in advance!