Spring Data: Not an managed type: class java.lang.Object

Question

I am trying to expose my db tables via spring boot by following different spring tutorials and I am running into following exception (I will post exception at the end).

Here are the classes that I am using

package com.xxx.xxx.db;

import org.springframework.data.repository.Repository;

import java.io.Serializable;

public interface BaseRepository<T, ID extends Serializable> extends Repository<T, ID>{
  T findOne(ID id);
  T save(T entity);
}

And here is my specific service class

package com.xxx.xxx.tablename;

import com.xxx.xxx.db.BaseRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class TableNameService {

  @Autowired
  private BaseRepository<TableName, Long> repository;

  public TableName findById(Long id){
    return repository.findOne(id);
  }
}

and here is my entity

package com.xxx.xxx.tablename;

import lombok.Getter;
import lombok.Setter;

import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.validation.constraints.NotNull;

@Getter
@Setter
@Entity
@Table(name="table_name")
public class TableName {

  @Id
  private long id;

  @NotNull
  private String name;

  public TableName() {
  }

  public TableName(long id){
    this.id = id;
  }

  public TableName(String name){
    this.name = name;
  }

  public TableName(long id, String name){
    this.id = id;
    this.name = name;
  }
}

My spring configurations are being done by application.yml file. The file currently have only database connection informaiton and nothing more than that

I also have a class named BeansConfig which is annotated by @Configuration. But this class is being used to validate if db properties which are being provided by application.yml are valid.

And now here is the exception

springframework.beans.factory.BeanCreationException: Error creating bean with name 'TableNameService': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.xxx.xxx.db.BaseRepository com.xxx.xxx.tablename.TableNameService.repository; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'baseRepository': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Not an managed type: class java.lang.Object
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:334)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1214)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:543)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:772)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:839)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:538)
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:118)
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:766)
    at org.springframework.boot.SpringApplication.createAndRefreshContext(SpringApplication.java:361)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:307)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1191)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1180)
    at com.xxx.xxx.Application.main(Application.java:12)
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.xxx.xxx.db.BaseRepository com.xxx.xxx.tablename.TableNameService.repository; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'baseRepository': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Not an managed type: class java.lang.Object
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:573)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:331)
    ... 17 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'baseRepository': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Not an managed type: class java.lang.Object
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1578)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1199)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1116)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1014)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:545)
    ... 19 common frames omitted
Caused by: java.lang.IllegalArgumentException: Not an managed type: class java.lang.Object
    at org.hibernate.jpa.internal.metamodel.MetamodelImpl.managedType(MetamodelImpl.java:219)
    at org.springframework.data.jpa.repository.support.JpaMetamodelEntityInformation.<init>(JpaMetamodelEntityInformation.java:68)
    at org.springframework.data.jpa.repository.support.JpaEntityInformationSupport.getEntityInformation(JpaEntityInformationSupport.java:67)
    at org.springframework.data.jpa.repository.support.JpaRepositoryFactory.getEntityInformation(JpaRepositoryFactory.java:152)
    at org.springframework.data.jpa.repository.support.JpaRepositoryFactory.getTargetRepository(JpaRepositoryFactory.java:99)
    at org.springframework.data.jpa.repository.support.JpaRepositoryFactory.getTargetRepository(JpaRepositoryFactory.java:81)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport.getRepository(RepositoryFactorySupport.java:185)
    at org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport.initAndReturn(RepositoryFactoryBeanSupport.java:251)
    at org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport.afterPropertiesSet(RepositoryFactoryBeanSupport.java:237)
    at org.springframework.data.jpa.repository.support.JpaRepositoryFactoryBean.afterPropertiesSet(JpaRepositoryFactoryBean.java:92)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1637)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1574)
    ... 29 common frames omitted

Answer 1

That's not possible the way you are trying. Since T needs to be an Entity, you need to type-restrict it. One option would be to make one repository per concrete Entity, but here you have a more generic way of implementing it:

Use a BaseClass for your entities:

@Entity
public abstract class BaseClass<IdType extends Serializable>{

    private IdType id;

    //Getter and setters

}

Define a @Repository for your base class:

@Repository
public interface Dao<T extends BaseClass, IdType extends Serializable> extends
        CrudRepository<T, IdType> {

}

You can define the shared entity operations in this interface and inherit from them for more concrete ones in the cases demanding it.

See also:

• How to implement a Spring Data repository for a @MappedSuperclass