JsonMappingException: unable to initialize proxy - no session

Question

I am creating a RESTful web service that consumes and returns JSON. I encounter the following stack trace when I try to retrieve an ESRBRating object from a database through a service level. However, when I insert the Spring Data JPA data repository directly into the controller and use it to get ESRBRating by ID, it works fine. However, when called through the service level, it does not work. I have provided the stack trace and code below. Can someone explain to me why this happens when viewing the service level, but not when directly accessing the Spring Data JPA data repository? How to solve this problem?

Stack trace

Caused by: org.hibernate.LazyInitializationException: could not initialize proxy - no Session at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:165) at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:286) at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.invoke(JavassistLazyInitializer.java:185) at net.jkratz.igdb.model.ESRBRating_$$_jvst319_0.getId(ESRBRating_$$_jvst319_0.java) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:466) at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:639) ... 76 more 

controller

 @RestController @RequestMapping(produces = "application/json", value="/esrbrating") public class ESRBRatingController { @Inject ESRBRatingService esrbRatingService; @Inject ESRBRatingRepository esrbRatingRepository; private Logger logger = LoggerFactory.getLogger(getClass()); /** * Returns all ESRB ratings in database * * @return List of ESRBRating objects * @see ESRBRating */ @RequestMapping(value = {"","/"}, method = RequestMethod.GET) public ResponseEntity<List<ESRBRating>> getESRBRatings() { List<ESRBRating> esrbRatings = esrbRatingService.getESRBRatings(); return new ResponseEntity<>(esrbRatings, HttpStatus.OK); } /** * Returns a single ESRB rating object if exists, otherwise returns HTTP status code 404 * * @param id ID of the ESRB Rating * @return ESRB Rating when found * @see ESRBRating */ @RequestMapping(value = "/{id}", method = RequestMethod.GET) public ResponseEntity<?> getUser(@PathVariable("id") Long id) { logger.debug("Attempting to fetch ESRB rating with ID: {}", id); ESRBRating esrbRating = esrbRatingService.getESRBRating(id); //ESRBRating esrbRating = esrbRatingRepository.findOne(id); if (esrbRating == null) { return new ResponseEntity<>("ESRB Rating not found", HttpStatus.NOT_FOUND); } else { return new ResponseEntity<>(esrbRating, HttpStatus.OK); } } } 

Service

 @Service @Transactional public class ESRBRatingServiceImpl implements ESRBRatingService { @Value("#{paging.games.maxPageSize}") private static int DEFAULT_PAGE_SIZE; @Value("#{paging.games.maxPageSize}") private static int MAX_PAGE_SIZE; @Inject private ESRBRatingRepository esrbRatingRepository; @Override public List<ESRBRating> getESRBRatings() { List<ESRBRating> ratings = esrbRatingRepository.findAll(); return ratings; } @Override public ESRBRating getESRBRating(Long id) { return esrbRatingRepository.getOne(id); } @Override public ESRBRating saveESRBRating(ESRBRating esrbRating) { return esrbRatingRepository.saveAndFlush(esrbRating); } @Override public boolean deleteESRBRating(Long id) { esrbRatingRepository.delete(id); return true; } } 

Repository

 package net.jkratz.igdb.repository; import net.jkratz.igdb.model.ESRBRating; import org.springframework.data.jpa.repository.JpaRepository; public interface ESRBRatingRepository extends JpaRepository<ESRBRating, Long> { } 

Model

 @Entity @Table(name = "esrb_rating", schema = "igdb") @JsonIgnoreProperties(ignoreUnknown = true) public class ESRBRating implements Serializable { private static final long serialVersionUID = 1L; @Id @NotNull @GeneratedValue(strategy = GenerationType.AUTO) @Column(name = "id", nullable = false) private Long id; @NotNull @Size(min = 1, max = 255) @Column(name = "title", nullable = false, length = 255) private String title; @Size(max = 65535) @Column(length = 65535) private String description; @OneToMany(cascade = CascadeType.ALL, mappedBy = "esrbRating") private List<Game> games; public ESRBRating() { } public ESRBRating(Long id, String title, String description) { this.id = id; this.title = title; this.description = description; } public Long getId() { return id; } public void setId(Long id) { this.id = id; } public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } public String getDescription() { return description; } public void setDescription(String description) { this.description = description; } @Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; ESRBRating that = (ESRBRating) o; return Objects.equal(this.id, that.id) && Objects.equal(this.title, that.title) && Objects.equal(this.description, that.description); } @Override public int hashCode() { return Objects.hashCode(id, title, description); } @Override public String toString() { return Objects.toStringHelper(this) .add("id", id) .add("title", title) .add("description", description) .toString(); } } 

This controller code works fine, going through the repository directly.

 @RestController @RequestMapping(produces = "application/json", value="/esrbrating") public class ESRBRatingController { @Inject ESRBRatingService esrbRatingService; @Inject ESRBRatingRepository esrbRatingRepository; private Logger logger = LoggerFactory.getLogger(getClass()); /** * Returns all ESRB ratings in database * * @return List of ESRBRating objects * @see ESRBRating */ @RequestMapping(value = {"","/"}, method = RequestMethod.GET) public ResponseEntity<List<ESRBRating>> getESRBRatings() { List<ESRBRating> esrbRatings = esrbRatingService.getESRBRatings(); return new ResponseEntity<>(esrbRatings, HttpStatus.OK); } /** * Returns a single ESRB rating object if exists, otherwise returns HTTP status code 404 * * @param id ID of the ESRB Rating * @return ESRB Rating when found * @see ESRBRating */ @RequestMapping(value = "/{id}", method = RequestMethod.GET) public ResponseEntity<?> getUser(@PathVariable("id") Long id) { logger.debug("Attempting to fetch ESRB rating with ID: {}", id); ESRBRating esrbRating = esrbRatingRepository.findOne(id); if (esrbRating == null) { return new ResponseEntity<>("ESRB Rating not found", HttpStatus.NOT_FOUND); } else { return new ResponseEntity<>(esrbRating, HttpStatus.OK); } } 

}

UPDATE:

I followed Randall Harley's advice and installed a reverse build with @JsonIgnore. However, now I get a completely different stack trace. It seems now Jackson / Spring doesn't know how to serialize ESRBRating. Any tips on this?

 org.springframework.http.converter.HttpMessageNotWritableException: Could not write content: No serializer found for class org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) ) (through reference chain: net.jkratz.igdb.model.ESRBRating_$$_jvstb5c_0["handler"]); nested exception is com.fasterxml.jackson.databind.JsonMappingException: No serializer found for class org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) ) (through reference chain: net.jkratz.igdb.model.ESRBRating_$$_jvstb5c_0["handler"]) at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.writeInternal(AbstractJackson2HttpMessageConverter.java:238) at org.springframework.http.converter.AbstractHttpMessageConverter.write(AbstractHttpMessageConverter.java:208) at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:158) at org.springframework.web.servlet.mvc.method.annotation.HttpEntityMethodProcessor.handleReturnValue(HttpEntityMethodProcessor.java:138) at org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:71) at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:122) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:781) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:721) at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:83) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:943) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966) at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857) at javax.servlet.http.HttpServlet.service(HttpServlet.java:620) at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842) at javax.servlet.http.HttpServlet.service(HttpServlet.java:727) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:118) at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:84) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:154) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:150) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.authentication.ui.DefaultLoginPageGeneratingFilter.doFilter(DefaultLoginPageGeneratingFilter.java:155) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:199) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:110) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:50) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87) at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192) at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160) at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:344) at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:261) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:314) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:745) Caused by: com.fasterxml.jackson.databind.JsonMappingException: No serializer found for class org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) ) (through reference chain: net.jkratz.igdb.model.ESRBRating_$$_jvstb5c_0["handler"]) at com.fasterxml.jackson.databind.ser.impl.UnknownSerializer.failForEmpty(UnknownSerializer.java:59) at com.fasterxml.jackson.databind.ser.impl.UnknownSerializer.serialize(UnknownSerializer.java:26) at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:505) at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:639) at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:152) at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:114) at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:1887) at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.writeInternal(AbstractJackson2HttpMessageConverter.java:231) ... 72 more 

Update 2:

In the end, I included @Proxy (lazy = false) in the ESRBRating class, and now it works great. However, I am curious what impact this might have on performance?

 @Entity @Table(name = "esrb_rating", schema = "igdb") @JsonIgnoreProperties(ignoreUnknown = false) @Proxy(lazy = false) public class ESRBRating implements Serializable { private static final long serialVersionUID = 1L; @Id @NotNull @GeneratedValue(strategy = GenerationType.AUTO) @Column(name = "id", nullable = false) private Long id; @NotNull @Size(min = 1, max = 255) @Column(name = "title", nullable = false, length = 255) private String title; @Size(max = 65535) @Column(length = 65535) private String description; @OneToMany(cascade = CascadeType.ALL, mappedBy = "esrbRating") private List<Game> games; public ESRBRating() { } public ESRBRating(Long id, String title, String description) { this.id = id; this.title = title; this.description = description; } public Long getId() { return id; } public void setId(Long id) { this.id = id; } public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } public String getDescription() { return description; } public void setDescription(String description) { this.description = description; } @JsonIgnore public List<Game> getGames() { return games; } public void setGames(List<Game> games) { this.games = games; } @Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; ESRBRating that = (ESRBRating) o; return Objects.equal(this.id, that.id) && Objects.equal(this.title, that.title) && Objects.equal(this.description, that.description); } @Override public int hashCode() { return Objects.hashCode(id, title, description); } @Override public String toString() { return Objects.toStringHelper(this) .add("id", id) .add("title", title) .add("description", description) .toString(); } } 

According to the Game class requested here

 @Entity @Table(name = "game", schema = "igdb", indexes = {@Index(name = "idx_game_title", columnList = ("title"), unique = false), @Index(name = "idx_game_developer", columnList = ("developer"), unique = false), @Index(name = "idx_game_publisher", columnList = ("publisher"), unique = false)}) @JsonIgnoreProperties(ignoreUnknown = true) public class Game implements Serializable { private static final long serialVersionUID = 1L; @Id @NotNull @GeneratedValue(strategy = GenerationType.AUTO) @Column(name = "id", nullable = false) private Long id; @NotNull @Size(min = 1, max = 255) @Column(name = "title", nullable = false, length = 255) private String title; @Size(max = 65535) @Column(name = "description", length = 65535) private String description; @Size(max = 255) @Column(name = "developer", length = 255) private String developer; @Size(max = 255) @Column(name = "publisher", length = 255) private String publisher; @NotNull @Size(max = 4) @Column(name = "players", nullable = false) private short players; @NotNull @Column(name = "cooperative", nullable = false) private boolean cooperative; @NotNull @Column(name = "release_date", nullable = false) @Temporal(TemporalType.DATE) private Date releaseDate; @Size(max = 255) @Column(name = "image", length = 255) private String image; @JoinColumn(name = "esrb_rating_id", referencedColumnName = "id", nullable = false) @ManyToOne(optional = false, fetch = FetchType.EAGER) private ESRBRating esrbRating; @OneToMany(cascade = CascadeType.ALL, mappedBy = "game") private List<GamePlatformMap> gamePlatformMap; @OneToMany(cascade = CascadeType.ALL, mappedBy = "game") private List<GameGenreMap> gameGenreMap; public Game() { } public Game(Long id, String title, String description, String developer, String publisher, short players, boolean cooperative, Date releaseDate, String image, ESRBRating esrbRating) { super(); this.id = id; this.title = title; this.description = description; this.developer = developer; this.publisher = publisher; this.players = players; this.cooperative = cooperative; this.releaseDate = releaseDate; this.image = image; this.esrbRating = esrbRating; } public Long getId() { return id; } public void setId(Long id) { this.id = id; } public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } public String getDescription() { return description; } public void setDescription(String description) { this.description = description; } public String getDeveloper() { return developer; } public void setDeveloper(String developer) { this.developer = developer; } public String getPublisher() { return publisher; } public void setPublisher(String publisher) { this.publisher = publisher; } public short getPlayers() { return players; } public void setPlayers(short players) { this.players = players; } public boolean isCooperative() { return cooperative; } public void setCooperative(boolean cooperative) { this.cooperative = cooperative; } public Date getReleaseDate() { return releaseDate; } public void setReleaseDate(Date releaseDate) { this.releaseDate = releaseDate; } public String getImage() { return image; } public void setImage(String image) { this.image = image; } public ESRBRating getEsrbRating() { return esrbRating; } public void setEsrbRating(ESRBRating esrbRating) { this.esrbRating = esrbRating; } @JsonIgnore public List<GamePlatformMap> getGamePlatformMap() { return gamePlatformMap; } public void setGamePlatformMap(List<GamePlatformMap> gamePlatformMap) { this.gamePlatformMap = gamePlatformMap; } @JsonIgnore public List<GameGenreMap> getGameGenreMap() { return gameGenreMap; } public void setGameGenreMap(List<GameGenreMap> gameGenreMap) { this.gameGenreMap = gameGenreMap; } @Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; Game that = (Game) o; return Objects.equal(this.id, that.id) && Objects.equal(this.title, that.title) && Objects.equal(this.description, that.description) && Objects.equal(this.developer, that.developer) && Objects.equal(this.publisher, that.publisher) && Objects.equal(this.players, that.players) && Objects.equal(this.cooperative, that.cooperative) && Objects.equal(this.releaseDate, that.releaseDate) && Objects.equal(this.image, that.image) && Objects.equal(this.esrbRating, that.esrbRating); } @Override public int hashCode() { return Objects.hashCode(id, title, description, developer, publisher, players, cooperative, releaseDate, image, esrbRating); } @Override public String toString() { return Objects.toStringHelper(this) .add("id", id) .add("title", title) .add("description", description) .add("developer", developer) .add("publisher", publisher) .add("players", players) .add("cooperative", cooperative) .add("releaseDate", releaseDate) .add("image", image) .add("esrbRating", esrbRating) .toString(); } } 

Answer 1

This usually happens when you return an object via @Responsebody (or to the response body of your case using @RestController), and the object is serialized, but has children that are not referenced in the LAZY collection. By the time you are in your controller, the active transaction ceases to be active, which will facilitate their receipt (for example, the one you started in your @Service). You can either make your EAGER sampling strategy by entering your collections by reference while in your transaction, or make your JSON Transient LAZY collections.

Answer 2

First download jackson-datatype-hibernate4-2.2.3.jar or higher version according to jackson-core version. Then use this code in the configuration file and you can use the LAZY Fetch Strategy without any errors.

 import com.fasterxml.jackson.databind.ObjectMapper; import com.fasterxml.jackson.datatype.hibernate4.Hibernate4Module; public class ApplicationConfig extends WebMvcConfigurerAdapter { public MappingJackson2HttpMessageConverter jacksonMessageConverter(){ MappingJackson2HttpMessageConverter messageConverter = new MappingJackson2HttpMessageConverter(); ObjectMapper mapper = new ObjectMapper(); //Registering Hibernate4Module to support lazy objects mapper.registerModule(new Hibernate4Module()); messageConverter.setObjectMapper(mapper); return messageConverter; } @Override public void configureMessageConverters(List<HttpMessageConverter<?>> converters) { //Here we add our custom-configured HttpMessageConverter converters.add(jacksonMessageConverter()); super.configureMessageConverters(converters); } 

Answer 3

@JsonIgnore annotations may solve your problem, but this leads to the fact that in this field, which you initially set as FetchType.LAZY, is completely ignored. It's better here. fooobar.com/questions/37305 / ...