How to solve org.springframework.core.convert.ConversionFailedException while fetching the data from DB using spring data jpa - spring-boot

Question

Domain Classes
#Data
#NoArgsConstructor
#AllArgsConstructor
#Entity
#Table(name = "SAMPLE_DATA")
#TypeDefs({
#TypeDef(name = "json", typeClass = JsonStringType.class),
#TypeDef(name = "jsonb", typeClass = JsonBinaryType.class)
})
public class Sample implements Serializable {
private static final long serialVersionUID = 1719868663566734198L;
#Id
private Long Id;
#Type(type = "json")
#Column(columnDefinition = "json",name = "person")
private Person personObj;
private String sampledata;
private String createdBy;
}
#Data
#NoArgsConstructor
#AllArgsConstructor
public class Person implements Serializable {
private static final long serialVersionUID = -5427425033242474312L;
private String firstName;
private String lastName;
}
Repository Class
#Repository
public interface SampleRepository extends JpaRepository<Sample, Long> {
#Query(value = "select s.personObj,s.sampledata from Sample s where s.Id=:Id")
List<Sample> findPersonById(Long Id);
}
To map to map JSON object types i m using
<dependency>
<groupId>com.vladmihalcea</groupId>
<artifactId>hibernate-types-52</artifactId>
<version>${hibernate-types.version}</version>
</dependency>
when I am trying to fetch the list of Sample object I am getting the following exception
org.springframework.core.convert.ConversionFailedException: Failed to convert from type [java.lang.Object[]] to type [#org.springframework.data.jpa.repository.Query com.domain.Sample] for value '[Person(firstName=abc, lastName=test)]'; nested exception is org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting from type [com.domain.Person] to type [#org.springframework.data.jpa.repository.Query com.domain.Sample]
.........
Caused by: org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting from type [com.domain.Person] to type [#org.springframework.data.jpa.repository.Query com.domain.Sample]

Answer 1

You don't have to select the distinct columns. You must select the Entity:
#Repository
public interface SampleRepository extends JpaRepository<Sample, Long> {
#Query(value = "select s from Sample s where s.Id=:Id")
List<Sample> findPersonById(Long Id);
}