An exception occurs when calling the openfeign method in @Async

Inizia riproducendo l’esempio con JDK 17, Spring Boot 2.7.2 e Spring Cloud 2021.0.3, quindi esamina UserController.feign() e UserRemoteService.users(), in particolare l’interazione tra @Async e @Cacheable. Il lavoro è completato quando il risultato di users() può essere iterato senza la LinkedHashMap-to-Users ClassCastException.

jdk:17 springboot:2.7.2 springcloud:2021.0.3
Here is my sample code

@RestController
@RequestMapping("user")
@RequiredArgsConstructor
public class UserController {

    private final UserRemoteService userRemoteService;

    @GetMapping
    public void users() {
        feign();
    }

    @Async
    public void feign() {
        userRemoteService.users()
                .forEach(System.out::println);
    }
}

@FeignClient(contextId = "userRemoteService", value = "feign-provider-biz",
        fallbackFactory = UserRemoteServiceFallbackFactory.class)
public interface UserRemoteService {

    @Cacheable(value = "users", key = "'user:all'", unless = "#result.empty")
    @GetMapping("/users")
    List<Users> users();
}

This is the resulting exception message

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.ClassCastException: class java.util.LinkedHashMap cannot be cast to class com.livk.provider.api.domain.Users (java.util.LinkedHashMap is in module java.base of loader 'bootstrap'; com.livk.provider.api.domain.Users is in unnamed module of loader 'app')
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1014) ~[spring-webmvc-5.3.22.jar:5.3.22]
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.3.22.jar:5.3.22]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:497) ~[jakarta.servlet-api-4.0.4.jar:4.0.4]
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.22.jar:5.3.22]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:584) ~[jakarta.servlet-api-4.0.4.jar:4.0.4]
	at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:74) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:129) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.22.jar:5.3.22]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.22.jar:5.3.22]
	at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.22.jar:5.3.22]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.22.jar:5.3.22]
	at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.22.jar:5.3.22]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.22.jar:5.3.22]
	at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.handlers.ServletChain$1.handleRequest(ServletChain.java:68) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.handlers.RedirectDirHandler.handleRequest(RedirectDirHandler.java:68) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:117) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) ~[undertow-core-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46) ~[undertow-core-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60) ~[undertow-core-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43) ~[undertow-core-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) ~[undertow-core-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.handlers.SendErrorPageHandler.handleRequest(SendErrorPageHandler.java:52) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) ~[undertow-core-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:275) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.handlers.ServletInitialHandler.access$100(ServletInitialHandler.java:79) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:134) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:131) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:48) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:255) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:79) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:100) ~[undertow-servlet-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.server.Connectors.executeRootHandler(Connectors.java:387) ~[undertow-core-2.2.18.Final.jar:2.2.18.Final]
	at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:852) ~[undertow-core-2.2.18.Final.jar:2.2.18.Final]
	at org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35) ~[jboss-threads-3.1.0.Final.jar:3.1.0.Final]
	at org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:2019) ~[jboss-threads-3.1.0.Final.jar:3.1.0.Final]
	at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1558) ~[jboss-threads-3.1.0.Final.jar:3.1.0.Final]
	at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1423) ~[jboss-threads-3.1.0.Final.jar:3.1.0.Final]
	at org.xnio.XnioWorker$WorkerThreadFactory$1$1.run(XnioWorker.java:1282) ~[xnio-api-3.8.7.Final.jar:3.8.7.Final]
	at java.base/java.lang.Thread.run(Thread.java:833) ~[na:na]
Caused by: java.lang.ClassCastException: class java.util.LinkedHashMap cannot be cast to class com.livk.provider.api.domain.Users (java.util.LinkedHashMap is in module java.base of loader 'bootstrap'; com.livk.provider.api.domain.Users is in unnamed module of loader 'app')
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1511) ~[na:na]
	at com.livk.consumer.biz.controller.UserController.feign(UserController.java:40) ~[main/:na]
	at com.livk.consumer.biz.controller.UserController.users(UserController.java:28) ~[main/:na]
	at com.livk.consumer.biz.controller.UserController$$FastClassBySpringCGLIB$$8198d4f5.invoke(<generated>) ~[main/:na]
	at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) ~[spring-core-5.3.22.jar:5.3.22]
	at org.springframework.aop.framework.CglibAopProxy.invokeMethod(CglibAopProxy.java:386) ~[spring-aop-5.3.22.jar:5.3.22]
	at org.springframework.aop.framework.CglibAopProxy.access$000(CglibAopProxy.java:85) ~[spring-aop-5.3.22.jar:5.3.22]
	at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:704) ~[spring-aop-5.3.22.jar:5.3.22]
	at com.livk.consumer.biz.controller.UserController$$EnhancerBySpringCGLIB$$58b999d5.users(<generated>) ~[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-5.3.22.jar:5.3.22]
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150) ~[spring-web-5.3.22.jar:5.3.22]
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117) ~[spring-webmvc-5.3.22.jar:5.3.22]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.3.22.jar:5.3.22]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) ~[spring-webmvc-5.3.22.jar:5.3.22]
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.3.22.jar:5.3.22]
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1070) ~[spring-webmvc-5.3.22.jar:5.3.22]
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963) ~[spring-webmvc-5.3.22.jar:5.3.22]
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.22.jar:5.3.22]
	... 51 common frames omitted

2022-07-22 15:31:34.917  INFO 23308 --- [ionShutdownHook] io.undertow                              : stopping server: Undertow - 2.2.18.Final
2022-07-22 15:31:34.919  INFO 23308 --- [ionShutdownHook] io.undertow.servlet                      : Destroying Spring FrameworkServlet 'dispatcherServlet'
2022-07-22 15:31:35.032  INFO 23308 --- [ionShutdownHook] o.s.c.c.s.ConsulServiceRegistry          : Deregistering service with consul: feign-consumer-8661

Process finished with exit code 130

When I call the openfeign method directly, this error does not occur, but an error occurs when I call it in @Async. The thread pool of @Async uses the default