class java.lang.String cannot be cast to class java.util.List (java.lang.String and java.util.List are in module java.base of loader 'bootstrap')

Question

Trying to use ReplyingKafkaTemplate to return the response from the service, but keep getting an error java.lang.ClassCastException: class java.lang.String cannot be cast to class java.util.List (java.lang.String and java.util.List are in module java.base of loader 'bootstrap')

Listener

 @KafkaListener(id = ProductTopicConstants.GET_PRODUCTS, topics = ProductTopicConstants.GET_PRODUCTS,splitIterables = false)
    @SendTo
    public List<Product> GetProducts(@Payload(required = false) String payload) {
        List<Product> products = _productRepository.findAll();
        return new ArrayList<>(products);
    }

KafkaConfiguration

@Configuration
public class KafkaConfiguration {
    @Bean
    public ReplyingKafkaTemplate<String, String, List<Product>> replyer(ProducerFactory<String, String> pf,
                                                                        ConcurrentKafkaListenerContainerFactory<String, List<Product>> containerFactory) {

        containerFactory.setReplyTemplate(kafkaTemplate(pf));
        ConcurrentMessageListenerContainer<String, List<Product>> container = replyContainer(containerFactory);
        ReplyingKafkaTemplate<String, String, List<Product>> replyer = new ReplyingKafkaTemplate<>(pf, container);
        return replyer;
    }

    @Bean
    public ConcurrentMessageListenerContainer<String, List<Product>> replyContainer(
            ConcurrentKafkaListenerContainerFactory<String, List<Product>> containerFactory) {

        ConcurrentMessageListenerContainer<String, List<Product>> container =
                containerFactory.createContainer(ProductTopicConstants.GET_PRODUCTS_CONTAINER);
        container.getContainerProperties().setGroupId(ProductTopicConstants.GET_PRODUCTS_CONTAINER);
        container.setBatchErrorHandler(new BatchLoggingErrorHandler());
        return container;
    }

    @Bean
    public KafkaTemplate<String, String> kafkaTemplate(ProducerFactory<String, String> pf) {
        return new KafkaTemplate<>(pf);
    }



   @Bean
    public NewTopic GetProducts() {
        return TopicBuilder.name(ProductTopicConstants.GET_PRODUCTS).partitions(1).replicas(1).build();
    }
    @Bean
    public NewTopic GetProductsContainer() {
        return TopicBuilder.name(ProductTopicConstants.GET_PRODUCTS_CONTAINER).partitions(1).replicas(1).build();
    }

}

service

@Service
public class ProductProducer implements IProductProducer{
  private final ReplyingKafkaTemplate<String, String, List<Product>> _replyTemplate;
    private static final Logger LOG = LoggerFactory.getLogger(ProductProducer.class);
    public ProductProducer(ReplyingKafkaTemplate<String, String, List<Product>> replyTemplate) {
        this._replyTemplate = replyTemplate;
    }

 @Override
    public List<ProductViewModel> GetProducts() throws InterruptedException, ExecutionException, TimeoutException {
        RequestReplyFuture<String, String, List<Product>> future =
                this._replyTemplate.sendAndReceive(new ProducerRecord<>(ProductTopicConstants.GET_PRODUCTS, 0, null, null));
            LOG.info(future.getSendFuture().get(10, TimeUnit.SECONDS).getRecordMetadata().toString());
            List<Product> value = future.get(10, TimeUnit.SECONDS).value(); --> Getting an error over here 
            return List.of(new ProductViewModel("","",0,""));
    }
}

Error

Getting an error over here List<Product> value = future.get(10, TimeUnit.SECONDS).value();

java.lang.ClassCastException: class java.lang.String cannot be cast to class java.util.List (java.lang.String and java.util.List are in module java.base of loader 'bootstrap')
    at fete.bird.fetebirdproduct.service.producer.ProductProducer.GetProducts(ProductProducer.java:40) ~[main/:na]
    at fete.bird.fetebirdproduct.api.v1.controller.ProductController.Products(ProductController.java:43) ~[main/:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[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:564) ~[na:na]
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:879) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:93) ~[spring-boot-actuator-2.3.1.RELEASE.jar:2.3.1.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) ~[na:na]
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) ~[na:na]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.36.jar:9.0.36]
    at java.base/java.lang.Thread.run(Thread.java:832) ~[na:na]

Configuration

spring:
  profiles:
    active: dev
  kafka:
    bootstrapAddress: localhost:9092
    producer:
      key-serializer: org.springframework.kafka.support.serializer.JsonSerializer
      value-serializer: org.springframework.kafka.support.serializer.JsonSerializer
    consumer:
      key-deserializer: org.springframework.kafka.support.serializer.JsonDeserializer
      value-deserializer: org.springframework.kafka.support.serializer.JsonDeserializer
      auto-offset-reset: earliest
      properties:
        spring:
          json:
            trusted:
              packages: *

Answer 1

I was missing '*' at the package

spring:
  profiles:
    active: dev
  kafka:
    bootstrapAddress: localhost:9092
    producer:
      key-serializer: org.springframework.kafka.support.serializer.JsonSerializer
      value-serializer: org.springframework.kafka.support.serializer.JsonSerializer
    consumer:
      key-deserializer: org.springframework.kafka.support.serializer.JsonDeserializer
      value-deserializer: org.springframework.kafka.support.serializer.JsonDeserializer
      auto-offset-reset: earliest
      properties:
        spring:
          json:
            trusted:
              packages: '*'