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I'm trying to build a repository with product class as entity. There seems to be something wrong with the Id generator.

Here's my product entity

Product.java

package com.example.repository.model; import org.hibernate.annotations.GenericGenerator; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; @Entity public class Product { @Id @GeneratedValue(strategy = GenerationType.AUTO, generator = "system-uuid") @GenericGenerator(name = "system-uuid", strategy = "uuid2") private Integer Id; private String name; private String type; private String description; private Double price; public Integer getId() { return Id; } public void setId(Integer id) { Id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getType() { return type; } public void setType(String type) { this.type = type; } public String getDescription() { return description; } public void setDescription(String description) { this.description = description; } public Double getPrice() { return price; } public void setPrice(Double price) { this.price = price; } }

Here's my application.properties

Application.properties

spring.datasource.url=jdbc:h2:~/Products spring.datasource.username=sa spring.datasource.password= spring.datasource.driver-class-name=org.h2.Driver spring.h2.console.path=/h2 spring.h2.console.enabled=true spring.jpa.hibernate.ddl-auto = update spring.jpa.show-sql=true

And here's the stack trace

2022-04-20 14:34:55.369 INFO 47972 --- [ main] o.hibernate.annotations.common.Version : HCANN000001: Hibernate Commons Annotations {5.1.2.Final} 2022-04-20 14:34:55.472 INFO 47972 --- [ main] org.hibernate.dialect.Dialect : HHH000400: Using dialect: org.hibernate.dialect.H2Dialect 2022-04-20 14:34:55.689 ERROR 47972 --- [ main] j.LocalContainerEntityManagerFactoryBean : Failed to initialize JPA EntityManagerFactory: [PersistenceUnit: default] Unable to build Hibernate SessionFactory; nested exception is org.hibernate.MappingException: Could not instantiate id generator [entity-name=com.example.repository.model.Product] 2022-04-20 14:34:55.690 WARN 47972 --- [ main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Invocation of init method failed; nested exception is javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory; nested exception is org.hibernate.MappingException: Could not instantiate id generator [entity-name=com.example.repository.model.Product] 2022-04-20 14:34:55.690 INFO 47972 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Shutdown initiated... 2022-04-20 14:34:55.758 INFO 47972 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Shutdown completed. 2022-04-20 14:34:55.769 INFO 47972 --- [ main] o.apache.catalina.core.StandardService : Stopping service [Tomcat] 2022-04-20 14:34:55.808 INFO 47972 --- [ main] ConditionEvaluationReportLoggingListener : Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled. 2022-04-20 14:34:55.843 ERROR 47972 --- [ main] o.s.boot.SpringApplication : Application run failed org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Invocation of init method failed; nested exception is javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory; nested exception is org.hibernate.MappingException: Could not instantiate id generator [entity-name=com.example.repository.model.Product] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1804) ~[spring-beans-5.3.18.jar:5.3.18] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:620) ~[spring-beans-5.3.18.jar:5.3.18] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542) ~[spring-beans-5.3.18.jar:5.3.18] at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.18.jar:5.3.18] at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.18.jar:5.3.18] at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.18.jar:5.3.18] at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.18.jar:5.3.18] at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1154) ~[spring-context-5.3.18.jar:5.3.18] at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:908) ~[spring-context-5.3.18.jar:5.3.18] at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) ~[spring-context-5.3.18.jar:5.3.18] at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145) ~[spring-boot-2.6.6.jar:2.6.6] at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:740) ~[spring-boot-2.6.6.jar:2.6.6] at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:415) ~[spring-boot-2.6.6.jar:2.6.6] at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) ~[spring-boot-2.6.6.jar:2.6.6] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1312) ~[spring-boot-2.6.6.jar:2.6.6] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1301) ~[spring-boot-2.6.6.jar:2.6.6] at com.example.repository.RepositoryApplication.main(RepositoryApplication.java:10) ~[classes/:na] Caused by: javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory; nested exception is org.hibernate.MappingException: Could not instantiate id generator [entity-name=com.example.repository.model.Product] at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:421) ~[spring-orm-5.3.18.jar:5.3.18] at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:396) ~[spring-orm-5.3.18.jar:5.3.18] at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341) ~[spring-orm-5.3.18.jar:5.3.18] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1863) ~[spring-beans-5.3.18.jar:5.3.18] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1800) ~[spring-beans-5.3.18.jar:5.3.18] ... 16 common frames omitted Caused by: org.hibernate.MappingException: Could not instantiate id generator [entity-name=com.example.repository.model.Product] at org.hibernate.id.factory.internal.DefaultIdentifierGeneratorFactory.createIdentifierGenerator(DefaultIdentifierGeneratorFactory.java:147) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final] at org.hibernate.mapping.SimpleValue.createIdentifierGenerator(SimpleValue.java:359) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final] at org.hibernate.mapping.SimpleValue.createIdentifierGenerator(SimpleValue.java:280) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final] at org.hibernate.internal.SessionFactoryImpl.lambda$new$1(SessionFactoryImpl.java:306) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final] at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183) ~[na:na] at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:177) ~[na:na] at java.base/java.util.HashMap$ValueSpliterator.forEachRemaining(HashMap.java:1675) ~[na:na] at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484) ~[na:na] at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474) ~[na:na] at java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150) ~[na:na] at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173) ~[na:na] at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[na:na] at java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:497) ~[na:na] at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:305) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final] at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:471) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final] at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:1498) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final] at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:58) ~[spring-orm-5.3.18.jar:5.3.18] at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365) ~[spring-orm-5.3.18.jar:5.3.18] at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:409) ~[spring-orm-5.3.18.jar:5.3.18] ... 20 common frames omitted Caused by: org.hibernate.HibernateException: Unanticipated return type [java.lang.Integer] for UUID conversion at org.hibernate.id.UUIDGenerator.configure(UUIDGenerator.java:96) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final] at org.hibernate.id.factory.internal.DefaultIdentifierGeneratorFactory.createIdentifierGenerator(DefaultIdentifierGeneratorFactory.java:142) ~[hibernate-core-5.6.7.Final.jar:5.6.7.Final] ... 38 common frames omitted

I'm totally new to spring and hibernate and have no idea how to solve this issue. Thanks in advance.

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  • Far too little information. You get an exception, please include it in your question. Not just the message the full stacktrace!. Commented Apr 20, 2022 at 9:16
  • Sure, my bad... Commented Apr 20, 2022 at 9:19
  • @M.Deinum Please upvote for better reach Commented Apr 20, 2022 at 9:20

1 Answer 1

Reset to default
4

Exception states:

Caused by: org.hibernate.HibernateException: Unanticipated return type [java.lang.Integer] for UUID conversion

Change id type to String. Integer is not supported for UUID generator:

@Id @GeneratedValue(strategy = GenerationType.AUTO, generator = "system-uuid") @GenericGenerator(name = "system-uuid", strategy = "uuid2") private String id;
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2 Comments

That worked, I was not aware of that. Thanks!
I don't have enough reputation to upvote yet. I tried it yesterday itself but wasn't able to. My bad.

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