Hibernate throws org hibernate AnnotationException No identifier specified for entity com domain idea MAE MFEView

Question

Why am I getting this exception   package com domain idea   import javax persistence CascadeType  import javax persistence Entity  import javax persistence FetchType  import javax persistence JoinColumn  import javax persistence OneToOne  import javax persistence Table   import org hibernate annotations AccessType          object model for the view  InvestmentReturn   vMAE MFE       Entity  Table name  vMAE MFE   schema  InvestmentReturn    AccessType  field   public class MAE MFEView                  trade property is a SuggestdTradeRecommendation object              OneToOne fetch   FetchType LAZY   cascade     CascadeType PERSIST         JoinColumn name    suggestedTradeRecommendationID       private SuggestedTradeRecommendation trade                  Most Adeverse Excursion value             private int MAE       public int getMAE                 return MAE                        Most Favorable Excursion value             private int MFE       public int getMFE                 return MFE                         return trade property        see  trade             public SuggestedTradeRecommendation getTrade                 return trade            Update  I ve changed my code to look like this     package com domain idea   import javax persistence CascadeType  import javax persistence FetchType  import javax persistence Entity  import javax persistence Id  import javax persistence JoinColumn  import javax persistence OneToOne  import javax persistence Table   import org hibernate annotations AccessType          object model for the view  InvestmentReturn   vMAE MFE       Entity  Table name  vMAE MFE   schema  InvestmentReturn    AccessType  field   public class MAE MFEView                  trade property is a SuggestdTradeRecommendation object              Id      OneToOne fetch   FetchType LAZY   cascade     CascadeType PERSIST         JoinColumn name    suggestedTradeRecommendationID       private SuggestedTradeRecommendation trade                  Most Adeverse Excursion value             private int MAE       public int getMAE                 return MAE                        Most Favorable Excursion value             private int MFE       public int getMFE                 return MFE                         return trade property        see  trade             public SuggestedTradeRecommendation getTrade                 return trade            but now I m getting this exception     Caused by  org hibernate MappingException  Could not determine type for  com domain idea SuggestedTradeRecommendation  at table  vMAE MFE  for columns   org hibernate mapping Column trade       at org hibernate mapping SimpleValue getType SimpleValue java 292      at org hibernate mapping SimpleValue isValid SimpleValue java 276      at org hibernate mapping RootClass validate RootClass java 216      at org hibernate cfg Configuration validate Configuration java 1135      at org hibernate cfg Configuration buildSessionFactory Configuration java 1320      at org hibernate cfg AnnotationConfiguration buildSessionFactory AnnotationConfiguration java 867      at org hibernate ejb Ejb3Configuration buildEntityManagerFactory Ejb3Configuration java 669          145 more

User · Answer

I know sounds crazy but I received such error because I forget to remove

private static final long serialVersionUID = 1L;

automatically generated by Eclipse JPA tool when a table to entities transformation I've done.

Removing the line above that solved the issue

User · Answer

This error occurs due to importing the wrong package import javax persistence Id  And you should always give the primary key to the table  otherwise it will give an error

User · Answer

You are missing a field annotated with  Id  Each  Entity needs an  Id - this is the primary key in the database    If you don t want your entity to be persisted in a separate table  but rather be a part of other entities  you can use  Embeddable instead of  Entity   If you want simply a data transfer object to hold some data from the hibernate entity  use no annotations on it whatsoever - leave it a simple pojo   Update  In regards to SQL views  Hibernate docs write      There is no difference between a view and a base table for a Hibernate mapping  This is transparent at the database level

User · Answer

Using  EmbeddableId for the PK entity has solved my issue    Entity  Table name  SAMPLE    public class SampleEntity implements Serializable     private static final long serialVersionUID   1L       EmbeddedId    SampleEntityPK id

User · Answer

TL DR You are missing the  Id entity property  and that s why Hibernate is throwing that exception  Entity identifiers Any JPA entity must have an identifier property  that is marked with the Id annotation  There are two types of identifiers   assigned auto-generated  Assigned identifiers An assigned identifier looks as follows   Id private Long id    Notice that we are using a wrapper  e g   Long  Integer  instead of a primitive type  e g   long  int   Using a wrapper type is a better choice when using Hibernate because  by checking if the id is null or not  Hibernate can better determine if an entity is transient  it does not have an associated table row  or detached  it has an associated table row  but it s not managed by the current Persistence Context    The assigned identifier must be set manually by the application prior to calling persist  Post post   new Post    post setId 1L    entityManager persist post    Auto-generated identifiers An auto-generated identifier requires the  GeneratedValue annotation besides the  Id   Id  GeneratedValue private int id   There are 3 strategies Hibernate can use to auto-generate the entity identifier   IDENTITY SEQUENCE TABLE  The IDENTITY strategy is to be avoided if the underlying database supports sequences  e g   Oracle  PostgreSQL  MariaDB since 10 3  SQL Server since 2012   The only major database that does not support sequences is MySQL   The problem with IDENTITY is that automatic Hibernate batch inserts are disabled for this strategy   The SEQUENCE strategy is the best choice unless you are using MySQL  For the  SEQUENCE strategy  you also want to use the pooled optimizer to reduce the number of database roundtrips when persisting multiple entities in the same Persistence Context  The TABLE generator is a terrible choice because it does not scale  For portability  you are better off using SEQUENCE by default and switch to IDENTITY for MySQL only

User · Answer

This error can be thrown when you import a different library for  Id than Javax persistance Id   You might need to pay attention this case too  In my case I had   import javax persistence Entity  import javax persistence GeneratedValue  import javax persistence Table   import org springframework data annotation Id    Entity public class Status         Id      GeneratedValue     private int id    when I change the code like this  it got worked  import javax persistence Entity  import javax persistence GeneratedValue  import javax persistence Table   import javax persistence Id    Entity public class Status         Id      GeneratedValue     private int id

User · Answer

I think this issue following model class wrong import       import org springframework data annotation Id    Normally  it should be       import javax persistence Id

User · Answer

The code below can solve the NullPointerException    Id  GeneratedValue  Column name    STOCK ID   unique   true  nullable   false  public Integer getStockId         return this stockId    public void setStockId Integer stockId        this stockId   stockId      If you add  Id  then you can declare some more like as above declared method

User · Answer

For me  javax persistence Id should be used instead of org springframework data annotation Id  For anyone who encountered this issue  you can check if you imported the right Id class

User · Answer

This error was caused by importing the wrong Id class  After changing org springframework data annotation Id to javax persistence Id the application run

[hibernate] Hibernate throws org.hibernate.AnnotationException: No identifier specified for entity: com..domain.idea.MAE_MFEView

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