Target state is not the requested interface org.neo4j.graphdb.Node but null

Question

I encountered some difficulties during playing with neo4j. Firstly, when I try to delete defined @EntityModel, I get an exception (Please, forgive me the quality of pics, the exception messages are also in question title):

My Controller (this is just for testing purpouse):

@Controller
public class HomeController {

@Autowired
PersonRepository personRepository;

@RequestMapping(value="/", method = RequestMethod.GET)
public String loadPage(final Model model, final HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) {

    Person person = new Person("My person");

    personRepository.save(person);

    personRepository.findOne(person.getId());

    return "home";
}

}

And model:

@NodeEntity
public class Person {

@GraphId
private Long id;

private String name;

public Person() {}

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

public String getName() {
    return name;
}

public void setName(final String name) {
    this.name = name;
}

public Long getId() {
    return id;
}

}

Configuration file:

 @Configuration
 @EnableTransactionManagement
 @EnableNeo4jRepositories(basePackages = "com.springapp.mvc.repository")
 @ComponentScan({"com.springapp.mvc"})
 public class PersistenceConfig extends Neo4jConfiguration {

@Bean
public GraphDatabaseService graphDatabaseService() {
    return new SpringRestGraphDatabase("http://localhost:7474/db/data");
}
}

My Repository:

public interface PersonRepository extends GraphRepository<Person> {

@Query("MATCH (n:Person{name: \"{namveValue}\"}) RETURN n;")
Person findByName(@Param("nameValue") final String name);
}

What am I doing wrong? I figured out that perhaps Person should implement org.neo4j.graphdb.Node and this is the source of these exceptions. However, having searched github repos I see that people do not implement this interface in their models. I have not found solution on stackoverflow so far.

Node exists in database but I cannot either delete it or save it. Please, help.

Answer 1

You are trying to see if a node with ID '0' exists as a person. Since the root node hasn't got a '__type__' property, the call will fail. SDN uses this property to determine the entity type of a node.

That being said, the exception seems to be caused by the following line:

if(! personRepository.exists(0L)) {