Spring-boot – How to use projections and specifications with spring data jpa

hibernatejpqlspring-bootspring-data-jpa

I'm not able to use Spring Data JPA projections and specifications together. I have the following setup:

Entity:

@Entity
public class Country {

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

    @Column(name = "NAME", nullable = false)
    private String name;

    @Column(name = "CODE", nullable = false)
    private String code;

    ---getters & setters---

}

Projection Interface:

public interface CountryProjection {
    String getName();
}

Country Specification:

public class CountrySpecification {
    public static Specification<Country> predicateName(final String name) {
        return new Specification<Country>() {
            @Override
            public Predicate toPredicate(Root<Country> eventRoot, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {
                return criteriaBuilder.equal(eventRoot.get(Country_.name), name);
            }
        };
    }
}

Repository:

public interface CountryRepository extends JpaRepository<Country, Long>, JpaSpecificationExecutor<Country> {
    List<CountryProjection> findByName(String name); // works fine
    List<CountryProjection> findAllProjectedBy(); // works fine
    List<CountryProjection> findAllProjectedBy(Specification<Country> specification); //throws Exception as shown below
}

The first two methods findByName and findAllProjectedBy works fine.
Whereas the third method findAllProjectedBy(Specification specification) throws the following exception –

Caused by: java.util.NoSuchElementException: null at
java.util.ArrayList$Itr.next(ArrayList.java:854) ~[na:1.8.0_102] at
java.util.Collections$UnmodifiableCollection$1.next(Collections.java:1042)
~[na:1.8.0_102] at
org.springframework.data.jpa.repository.query.CriteriaQueryParameterBinder.bind(CriteriaQueryParameterBinder.java:63)
~[spring-data-jpa-1.10.6.RELEASE.jar:na] at
org.springframework.data.jpa.repository.query.ParameterBinder.bind(ParameterBinder.java:100)
~[spring-data-jpa-1.10.6.RELEASE.jar:na] at
org.springframework.data.jpa.repository.query.ParameterBinder.bindAndPrepare(ParameterBinder.java:160)
~[spring-data-jpa-1.10.6.RELEASE.jar:na] at
org.springframework.data.jpa.repository.query.ParameterBinder.bindAndPrepare(ParameterBinder.java:151)
~[spring-data-jpa-1.10.6.RELEASE.jar:na] at
org.springframework.data.jpa.repository.query.PartTreeJpaQuery$QueryPreparer.invokeBinding(PartTreeJpaQuery.java:218)
~[spring-data-jpa-1.10.6.RELEASE.jar:na] at
org.springframework.data.jpa.repository.query.PartTreeJpaQuery$QueryPreparer.createQuery(PartTreeJpaQuery.java:142)
~[spring-data-jpa-1.10.6.RELEASE.jar:na] at
org.springframework.data.jpa.repository.query.PartTreeJpaQuery.doCreateQuery(PartTreeJpaQuery.java:78)
~[spring-data-jpa-1.10.6.RELEASE.jar:na] at
org.springframework.data.jpa.repository.query.AbstractJpaQuery.createQuery(AbstractJpaQuery.java:190)
~[spring-data-jpa-1.10.6.RELEASE.jar:na] at
org.springframework.data.jpa.repository.query.JpaQueryExecution$CollectionExecution.doExecute(JpaQueryExecution.java:118)
~[spring-data-jpa-1.10.6.RELEASE.jar:na] at
org.springframework.data.jpa.repository.query.JpaQueryExecution.execute(JpaQueryExecution.java:82)
~[spring-data-jpa-1.10.6.RELEASE.jar:na] at
org.springframework.data.jpa.repository.query.AbstractJpaQuery.doExecute(AbstractJpaQuery.java:116)
~[spring-data-jpa-1.10.6.RELEASE.jar:na] at
org.springframework.data.jpa.repository.query.AbstractJpaQuery.execute(AbstractJpaQuery.java:106)
~[spring-data-jpa-1.10.6.RELEASE.jar:na] at
org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:482)
~[spring-data-commons-1.12.6.RELEASE.jar:na] at
org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:460)
~[spring-data-commons-1.12.6.RELEASE.jar:na] at
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
~[spring-aop-4.3.5.RELEASE.jar:4.3.5.RELEASE] at
org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:61)
~[spring-data-commons-1.12.6.RELEASE.jar:na] at
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
~[spring-aop-4.3.5.RELEASE.jar:4.3.5.RELEASE] at
org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
~[spring-tx-4.3.5.RELEASE.jar:4.3.5.RELEASE] at
org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:282)
~[spring-tx-4.3.5.RELEASE.jar:4.3.5.RELEASE] at
org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
~[spring-tx-4.3.5.RELEASE.jar:4.3.5.RELEASE] at
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
~[spring-aop-4.3.5.RELEASE.jar:4.3.5.RELEASE] at
org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136)
~[spring-tx-4.3.5.RELEASE.jar:4.3.5.RELEASE] at
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
~[spring-aop-4.3.5.RELEASE.jar:4.3.5.RELEASE] at
org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:133)
~[spring-data-jpa-1.10.6.RELEASE.jar:na] at
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
~[spring-aop-4.3.5.RELEASE.jar:4.3.5.RELEASE] at
org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
~[spring-aop-4.3.5.RELEASE.jar:4.3.5.RELEASE] at
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
~[spring-aop-4.3.5.RELEASE.jar:4.3.5.RELEASE] at
org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213)
~[spring-aop-4.3.5.RELEASE.jar:4.3.5.RELEASE] at
com.sun.proxy.$Proxy82.findAllProjectedBy(Unknown Source) ~[na:na] at
com.mmp.data.jpa.DataJpaApplication.run(DataJpaApplication.java:42)
[classes/:na] at
org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:800)
[spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE] … 11 common frames
omitted

How can this be achieved? Any ideas?

Best Answer

The ability to mix Projections and Specifications are not yet supported. There is a bug tracking this.

Related Topic