No serializer found for class org hibernate proxy pojo javassist Javassist

Question

I am working on SpringMVC  Hibernate  amp  JSON but I am getting this error    HTTP Status 500 - Could not write JSON  No serializer found for class org hibernate proxy pojo javassist JavassistLazyInitializer and no properties discovered to create BeanSerializer  to avoid exception  disable SerializationConfig SerializationFeature FAIL ON EMPTY BEANS       Please check my Entity below       Entity  Table name  USERS   public class User         Id      GeneratedValue      Column name  USER ID       private Integer userId        Column name  USER FIRST NAME       private String firstName        Column name  USER LAST NAME       private String lastName         Column name  USER MIDDLE NAME       private String middleName        Column name  USER EMAIL ID       private String emailId        Column name  USER PHONE NO       private Integer phoneNo        Column name  USER PASSWORD       private String password        Column name  USER CONF PASSWORD       private String  confPassword        Transient     private String token        Column name  USER CREATED ON       private Date createdOn        OneToMany fetch FetchType EAGER cascade CascadeType ALL       Fetch value   FetchMode SUBSELECT       JoinTable name    USER ROLES   joinColumns      JoinColumn name    USER ID      inverseJoinColumns      JoinColumn name    ROLE ID          private List lt ActifioRoles gt  userRole   new ArrayList lt ActifioRoles gt            OneToMany fetch FetchType EAGER cascade CascadeType ALL mappedBy  userDetails        Fetch value   FetchMode SUBSELECT      private List lt com actifio domain Address gt  userAddress   new ArrayList lt com actifio domain Address gt           OneToOne cascade CascadeType ALL      private Tenant tenantDetails        public Integer getUserId             return userId            public void setUserId Integer userId            this userId   userId            public String getFirstName             return firstName            public void setFirstName String firstName            this firstName   firstName            public String getLastName             return lastName            public void setLastName String lastName            this lastName   lastName            public String getEmailId             return emailId            public void setEmailId String emailId            this emailId   emailId            public String getPassword             return password            public void setPassword String password            this password   password            public String getConfPassword             return confPassword            public void setConfPassword String confPassword            this confPassword   confPassword            public Date getCreatedOn             return createdOn            public void setCreatedOn Date createdOn            this createdOn   createdOn             public List lt ActifioRoles gt  getUserRole             return userRole             public void setUserRole List lt ActifioRoles gt  userRole            this userRole   userRole            public String getMiddleName             return middleName            public void setMiddleName String middleName            this middleName   middleName            public Integer getPhoneNo             return phoneNo            public void setPhoneNo Integer phoneNo            this phoneNo   phoneNo             public List lt com actifio domain Address gt  getUserAddress             return userAddress            public void setUserAddress List lt com actifio domain Address gt  userAddress            this userAddress   userAddress            public Tenant getTenantDetails             return tenantDetails            public void setTenantDetails Tenant tenantDetails            this tenantDetails   tenantDetails            public String getToken             return token            public void setToken String token            this token   token                 How can I Solve this

User · Answer

JsonIgnoreProperties   quot hibernateLazyInitializer quot   quot handler quot    it works for me

User · Answer

Add this Annotation to Entity Class  Model  that works for me this cause lazy loading via the hibernate proxy object       JsonIgnoreProperties   hibernateLazyInitializer    handler

User · Answer

Or you could configure mapper as       custom configuration for lazy loading  public static class HibernateLazyInitializerSerializer extends JsonSerializer lt JavassistLazyInitializer gt          Override     public void serialize JavassistLazyInitializer initializer  JsonGenerator jsonGenerator              SerializerProvider serializerProvider              throws IOException  JsonProcessingException           jsonGenerator writeNull              and configure mapper       mapper   new JacksonMapper        SimpleModule simpleModule   new SimpleModule               SimpleModule   new Version 1 0 0 null             simpleModule addSerializer              JavassistLazyInitializer class              new HibernateLazyInitializerSerializer              mapper registerModule simpleModule

User · Answer

I changed  in Annotation model class      fetch   FetchType LAZY   to      fetch   FetchType EAGER   and worked in pretty way     Love it

User · Answer

There are two ways to fix the problem   Way 1   Add  spring jackson serialization fail-on-empty-beans false into application properties  Way 2    Use join fetch in JPQL query to retrieve parent object data  see below    Query value    select child from Child child join fetch child parent Parent               countQuery    select count    from Child child join child parent parent    public Page lt Parent gt  findAll Pageable pageable

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This is an issue with Jackson  To prevent this  instruct Jackson not to serialize nested relationship or nested class    Look at the following example  Address class mapped to City  State  and Country classes and the State itself is pointing to Country and Country pointing to Region  When your get address values through Spring boot REST API you will get the above error  To prevent it  just serialize mapped class   which reflects level one JSON  and ignore nested relationships with         JsonIgnoreProperties value     state     JsonIgnoreProperties value     country    and  JsonIgnoreProperties value     region     This will prevent Lazyload exception along with the above error  Use the below code as an example and change your model classes   Address java   Entity public class Address extends AbstractAuditingEntity       private static final long serialVersionUID   4203344613880544060L        Id      GeneratedValue strategy   GenerationType IDENTITY       Column name    id       private Long id        Column name    street name       private String streetName        Column name    apartment       private String apartment        ManyToOne      JoinColumn name    city id        JsonIgnoreProperties value     state        private City city        ManyToOne      JoinColumn name    state id        JsonIgnoreProperties value     country        private State state        ManyToOne      JoinColumn name    country id        JsonIgnoreProperties value     region        private Country country        ManyToOne      JoinColumn name    region id       private Region region        Column name    zip code       private String zipCode        ManyToOne      JoinColumn name    address type id   referencedColumnName    id       private AddressType addressType       City java   EqualsAndHashCode callSuper   true   Entity  Table name    city    Cache region    cityCache  usage   CacheConcurrencyStrategy READ WRITE   Data public class City extends AbstractAuditingEntity       private static final long serialVersionUID   -8825045541258851493L        Id      Column name    id        GeneratedValue strategy   GenerationType IDENTITY      private Long id        Column name    name          Length max   100 min   2      private String name         ManyToOne      JoinColumn name    state id       private State state      State java   Entity  Table name    state    Data  EqualsAndHashCode callSuper   true  public class State extends AbstractAuditingEntity       private static final long serialVersionUID   5553856435782266275L        Id      Column name    id        GeneratedValue strategy   GenerationType IDENTITY      private Long id        Column name    code       private String code        Column name    name        Length max   200  min   2      private String name        ManyToOne fetch   FetchType LAZY       JoinColumn name    country id       private Country country       Country java   Entity  Table name    country    Data  EqualsAndHashCode callSuper   true  public class Country extends AbstractAuditingEntity       private static final long serialVersionUID   6396100319470393108L        Id      Column name    id        GeneratedValue strategy   GenerationType IDENTITY      private Long id        Column name    name        Length max   200  min   2      private String name        Column name    code        Length max   3  min   2      private String code        Column name    iso code        Length max   3  min   2      private String isoCode        ManyToOne      JoinColumn name    region id       private Region region

User · Answer

It could be your Hibernate entity relationship causing the issue   simply stop lazy loading of that related entity   for example   I resolved below by setting lazy  false  for customerType    lt class name  Customer  table  CUSTOMER  gt           lt id name  custId  type  long  gt               lt column name  CUSTID    gt               lt generator class  assigned    gt           lt  id gt           lt property name  name  type  java lang String  gt               lt column name  NAME    gt           lt  property gt           lt property name  phone  type  java lang String  gt               lt column name  PHONE    gt           lt  property gt           lt property name  pan  type  java lang String  gt               lt column name  PAN    gt           lt  property gt            lt many-to-one name  customerType  not-null  true  lazy  false  gt  lt  many-to-one gt       lt  class gt   lt  hibernate-mapping gt

User · Answer

This Exception      org springframework http converter HttpMessageNotWritableException   getting because  I hope so  your are sending response output as Serializable object   This is problem occurring in  spring  To over come this issue  send POJO object as response output   Example         Entity      Table name  user details       public class User implements Serializable            Id          GeneratedValue strategy  GenerationType IDENTITY           Column name  id           private Integer id            Column name  user name           private String userName            Column name  email id           private String emailId            Column name  phone no           private String phone     setter and getters   POJO class   public class UserVO        private int Id      private String userName      private String emailId      private String phone      private Integer active     setter and getters   In controller convert the serilizable object fields to POJO class fields and return pojo class as output            User u  userService getdetials       get data from database          UserVO userVo  new UserVO        created pojo class object          userVo setId u getId             userVo setEmailId u getEmailId             userVo setActive u getActive             userVo setPhone u getPhone             userVo setUserName u getUserName            retunr userVo     finally send pojo object as output

User · Answer

As it is correctly suggested in previous answers  lazy loading means that when you fetch your object from the database  the nested objects are not fetched  and may be fetched later when required    Now Jackson tries to serialize the nested object     make JSON out of it   but fails as it finds JavassistLazyInitializer instead of normal object  This is the error you see  Now  how to solve it   As suggested by CP510 previously  one option is to suppress the error by this line of configuration    spring jackson serialization fail-on-empty-beans false   But this is dealing with the symptoms  not the cause  To solve it elegantly  you need to decide whether you need this object in JSON or not    Should you need the object in JSON  remove the FetchType LAZY option from the field that causes it  it might also be a field in some nested object  not only in the root entity you are fetching   If do not need the object in JSON  annotate the getter of this field  or the field itself  if you do not need to accept incoming values either  with  JsonIgnore  for example        this field will not be serialized to from JSON  JsonIgnore private NestedType secret      Should you have more complex needs  e g  different rules for different REST controllers using the same entity   you can use jackson views or filtering or for very simple use case  fetch nested objects separately

User · Answer

Just to add this in  I ran into this same issue  but the supplied answers did not work  I fixed it by taking the exception s suggestion and adding to the application properties file     spring jackson serialization fail-on-empty-beans false   I m using Spring Boot v1 3 with Hibernate 4 3  It now serializes the entire object and nested objects   EDIT  2018  Since this still gets comments I ll clarify here  This absolutely only hides the error  The performance implications are there  At the time  I needed something to deliver and work on it later  which I did via not using spring anymore   So yes  listen to someone else if you really want to solve the issue  If you just want it gone for now go ahead and use this answer  It s a terrible idea  but heck  might work for you  For the record  never had a crash or issue again after this  But it is probably the source of what ended up being a SQL performance nightmare

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For Hibernate you can use the jackson-datatype-hibernate project to accommodate JSON serialization deserialization with lazy-loaded objects   For example   import com fasterxml jackson databind Module  import com fasterxml jackson datatype hibernate5 Hibernate5Module  import org springframework context annotation Bean  import org springframework context annotation Configuration    Configuration public class JacksonDatatypeHibernate5Configuration           Register Jackson Hibernate5 Module to handle JSON serialization of lazy-loaded entities        Any beans of type com fasterxml jackson databind Module are automatically        registered with the auto-configured Jackson2ObjectMapperBuilder        https   docs spring io spring-boot docs current reference html howto-spring-mvc html howto-customize-the-jackson-objectmapper      Bean     public Module hibernate5Module             Hibernate5Module hibernate5Module   new Hibernate5Module            hibernate5Module enable  Hibernate5Module Feature FORCE LAZY LOADING            hibernate5Module disable  Hibernate5Module Feature USE TRANSIENT ANNOTATION            return hibernate5Module

User · Answer

it works for me    JsonIgnoreProperties   hibernateLazyInitializer   handler      e g    Entity  Table name    user    Data  NoArgsConstructor  JsonIgnoreProperties   hibernateLazyInitializer   handler    public class User         Id      GeneratedValue strategy   GenerationType IDENTITY      private Long id       private String name       private Date created

User · Answer

I had a similar problem with lazy loading via the hibernate proxy object  Got around it by annotating the class having lazy loaded private properties with    JsonIgnoreProperties   hibernateLazyInitializer    handler      I assume you can add the properties on your proxy object that breaks the JSON serialization to that annotation   The problem is that entities are loaded lazily and serialization happens before they get loaded fully    Hibernate initialize  lt your getter method gt

User · Answer

You could use the add-on module for Jackson which handles Hibernate lazy-loading   More info on https   github com FasterXML jackson-datatype-hibernate wich support hibernate 3 and 4 separately

User · Answer

The solution is inspired from the below solution by  marco  I have also updated his answer with these datails   The problem here is about lazy loading of the sub-objects  where Jackson only finds hibernate proxies  instead of full blown objects    So we are left with two options - Suppress the exception  like done above in most voted answer here  or make sure that the LazyLoad objects are loaded   If you choose to go with latter option  solution would be to use jackson-datatype library  and configure the library to initialize lazy-load dependencies prior to the serialization   I added a new config class to do that    Configuration public class JacksonConfig extends WebMvcConfigurerAdapter     Bean  Primary public MappingJackson2HttpMessageConverter jacksonMessageConverter        MappingJackson2HttpMessageConverter messageConverter   new MappingJackson2HttpMessageConverter        ObjectMapper mapper   new ObjectMapper        Hibernate5Module module   new Hibernate5Module        module enable Hibernate5Module Feature FORCE LAZY LOADING       mapper registerModule module       messageConverter setObjectMapper mapper       return messageConverter          Primary makes sure that no other Jackson config is used for initializing any other beans   Bean is as usual  module enable Hibernate5Module Feature FORCE LAZY LOADING   is to enable Lazy loading of the dependencies   Caution - Please watch for its performance impact  sometimes EAGER fetch helps  but even if you make it eager  you are still going to need this code  because proxy objects still exist for all other Mappings except  OneToOne  PS   As a general comment  I would discourage the practice of sending whole data object back in the Json response  One should be using Dto s for this communication  and use some mapper like mapstruct to map them  This saves you from accidental security loopholes  as well as above exception

User · Answer

I think that the problem is the way that you retrieve the entity   Maybe you are doing something like this   Person p    Person  session load Person class  new Integer id      Try using the method get instead of load  Person p    Person  session get Person class  new Integer id      The problem is that with load method you get just a proxy but not the real object  The proxy object doesn t have the properties already loaded so when the serialization happens there are no properties to be serialized  With the get method you actually get the real object  this object could in fact be serialized

User · Answer

I ve the same problem right now  check if you fix fetch in lazy with a  jsonIQgnore   ManyToOne fetch   FetchType LAZY   JoinColumn name  teachers    JsonIgnoreProperties  course   Teacher teach    Just delete the   fetch       or the annotation   jsonIgnore  and it will work   ManyToOne  JoinColumn name  teachers    JsonIgnoreProperties  course   Teacher teach

User · Answer

In the Hibernate 5 2 and above  you able to remove the hibernate proxy as below  it will give you the actual object so you can serialize it properly   Object unproxiedEntity   Hibernate unproxy  proxy

User · Answer

Try   implements interface Serializable

[json] No serializer found for class org.hibernate.proxy.pojo.javassist.Javassist?

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