Unable to add a second entity to Spring data starter project

Question

I got the Spring Data JPA starter project from https://spring.io/guides/gs/accessing-data-jpa/. I can create the Customer and CustomerRepository classes and make the Customer entity persist.

However when I add another entity Person and a PersonRepository and try to persist the entity I get an error shown below. It is like within Application.java there is some sort of inner class $1 that Spring data is try to map as an entity.

java.lang.IllegalArgumentException: Unknown entity: hello.Application$1

package hello;

import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
@ToString
@NoArgsConstructor
@Data
public class Person {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    private int age;
}

package hello;

import org.springframework.data.repository.CrudRepository;

public interface PersonRepository extends CrudRepository<Person, Long> {
}

package hello;

import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
@Slf4j
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class);
    }

    /*
    @Bean
    public CommandLineRunner demo(CustomerRepository repository) {
        return (args) -> {
            repository.save(new Customer("Jack", "Bauer"));
            repository.save(new Customer("Chole", "O'Brian"));
            repository.save(new Customer("Kim", "Bauer"));
            repository.save(new Customer("David", "Palmer"));
            repository.save(new Customer("Michelle", "Dessler"));

            // fetch all customers
            log.info("Customers found with findAll():");
            log.info("-------------------------------");
            repository.findAll().forEach(c -> log.info(c.toString()));
        };
    }
    */

    @Bean
    public CommandLineRunner demo(PersonRepository repository) {
        return (args) -> {
            repository.save(new Person(){{
                setAge(20);
            }});

            // fetch all customers
            log.info("Customers found with findAll():");
            log.info("-------------------------------");
            repository.findAll().forEach(c -> log.info(c.toString()));
        };
    }
}

java.lang.IllegalStateException: Failed to execute CommandLineRunner at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:782) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE] at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:763) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:318) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1213) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1202) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE] at hello.Application.main(Application.java:14) [classes/:na] Caused by: org.springframework.dao.InvalidDataAccessApiUsageException: Unknown entity: hello.Application$1; nested exception is java.lang.IllegalArgumentException: Unknown entity: hello.Application$1 at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:373) ~[spring-orm-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:255) ~[spring-orm-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:527) ~[spring-orm-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:61) ~[spring-tx-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:242) ~[spring-tx-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:153) ~[spring-tx-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:138) ~[spring-data-jpa-2.1.9.RELEASE.jar:2.1.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:93) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:61) ~[spring-data-commons-2.1.9.RELEASE.jar:2.1.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE] at com.sun.proxy.$Proxy67.save(Unknown Source) ~[na:na] at hello.Application.lambda$demo$1(Application.java:38) [classes/:na] at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:779) [spring-boot-2.1.6.RELEASE.jar:2.1.6.RELEASE] ... 5 common frames omitted Caused by: java.lang.IllegalArgumentException: Unknown entity: hello.Application$1 at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:804) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final] at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:785) ~[hibernate-core-5.3.10.Final.jar:5.3.10.Final] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_181] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_181] at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_181] at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:308) ~[spring-orm-5.1.8.RELEASE.jar:5.1.8.RELEASE] at com.sun.proxy.$Proxy65.persist(Unknown Source) ~[na:na] at org.springframework.data.jpa.repository.support.SimpleJpaRepository.save(SimpleJpaRepository.java:507) ~[spring-data-jpa-2.1.9.RELEASE.jar:2.1.9.RELEASE] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_181] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_181] at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_181] at org.springframework.data.repository.core.support.RepositoryComposition$RepositoryFragments.invoke(RepositoryComposition.java:359) ~[spring-data-commons-2.1.9.RELEASE.jar:2.1.9.RELEASE] at org.springframework.data.repository.core.support.RepositoryComposition.invoke(RepositoryComposition.java:200) ~[spring-data-commons-2.1.9.RELEASE.jar:2.1.9.RELEASE] at org.springframework.data.repository.core.support.RepositoryFactorySupport$ImplementationMethodExecutionInterceptor.invoke(RepositoryFactorySupport.java:644) ~[spring-data-commons-2.1.9.RELEASE.jar:2.1.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:608) ~[spring-data-commons-2.1.9.RELEASE.jar:2.1.9.RELEASE] at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.lambda$invoke$3(RepositoryFactorySupport.java:595) ~[spring-data-commons-2.1.9.RELEASE.jar:2.1.9.RELEASE] at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:595) ~[spring-data-commons-2.1.9.RELEASE.jar:2.1.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:59) ~[spring-data-commons-2.1.9.RELEASE.jar:2.1.9.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:295) ~[spring-tx-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98) ~[spring-tx-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.8.RELEASE.jar:5.1.8.RELEASE] at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139) ~[spring-tx-5.1.8.RELEASE.jar:5.1.8.RELEASE] ... 16 common frames omitted

Lesiak · Accepted Answer · 2019-07-25T18:50:34.740

2

The error message clearly says you have an unmapped class. You correctly deducted that

It is like within Application.java there is some sort of inner class $1 that Spring data is try to map as an entity.

The inner class in question is defined in your code as a subclass of Person

repository.save(new Person(){{
    setAge(20);
}});

The class is an Anonymous Inner Class, with an Instance Initializer block. See What is an initialization block?

Use the following code to create a new person without subclassing it:

Person p = new Person();
p.setAge(20);
repository.save(p)

edited Jul 25 '19 at 18:50

answered Jul 25 '19 at 18:45

Lesiak

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Thanks @Lesiak, that did resolve my issue. For some reason I was under the impression that ```repository.save(new Person(){{ setAge(20); }});``` and ```Person p = new Person(); p.setAge(20); repository.save(p)``` are equivalent code. I will read up on the Anonymous Inner Class initialization block thread you provided the link for. – sshekhar Jul 26 '19 at 02:40
Btw, I see the error message `Unknown entity: hello.Application$1`. This means that the code `new Person(){{ setAge(20); }})` is creating an anonymous inner class within `Application.java` and making that anonymous inner class extend `Person.java`. – sshekhar Jul 26 '19 at 03:28
Precisely. Note that every time you have `new Person(){{ setAge(20); }})`, a new class is created, even if the initialization block is identical (or empty). This is why this construction in most cases should be avoided. – Lesiak Jul 26 '19 at 04:39
Thank you again! I learned something new. Really appreciate the time you took to help me out! – sshekhar Jul 26 '19 at 11:50

Unable to add a second entity to Spring data starter project

1 Answers1