Spring Data MongoDB doesn't see enabled by default Joda-Time converter

Question

I try to just save a document with org.joda.time.DateTime field from Joda-Time.

@Document
public class JodaDoc {

    @Id
    private BigInteger id;

    private String dateAsString;

    private DateTime date;

    public JodaDoc(String dateAsString, DateTime date) {
        this.dateAsString = dateAsString;
        this.date = date;
    }

    public BigInteger getId() { return id; }

    public String getDateAsString() { return dateAsString; }

    public DateTime getDate() { return date; }
}

Standard application config using AbstractMongoConfiguration from spring-data-mongodb:

@ComponentScan
@EnableMongoRepositories
public class AppConfig extends AbstractMongoConfiguration { ... }

A test which explicit uses AppConfig class (with Spock, but internally mechanisms provided by spring-test are used):

@ContextConfiguration(classes = AppConfig)
class JodaDocRepositorySpec extends Specification {

    @Autowired
    private JodaDocRepository jodaDocRepository

    def "save document with DateTime"() {
        given:
            def jodaDoc = new JodaDoc(DateTime.now())
        when:
            def savedJodaDoc = jodaDocRepository.save(jodaDoc)
        then:
            savedJodaDoc.id
    }
}

Joda-Time converters in Spring Data MongoDB (and also in Spring Core itself) should be enabled by default when Joda-Time jar is on a classpath. Unfortunately my test fails with:

org.springframework.core.convert.ConverterNotFoundException:
No converter found capable of converting from type org.joda.time.DateTime to type java.util.Date

I tried to add DefaultFormattingConversionService:

@Bean
public ConversionService conversionService() {
    return new DefaultFormattingConversionService();
}

ConversionServiceFactoryBean and a few other things with no effect. I wasn't able to find an answer on StackOverflow.

Question. Why Spring Data MongoDB doesn't see a standard org.joda.time.DateTime -> java.util.Date conveter?

Answer 1

It took me some time and I want to share the solution with others.

I created a small quickstart application and wasn't able to reproduce the issue. At the end I discovered that the problem was a missing @Configuration annotation in my configuration class. With:

@Configuration
@ComponentScan
@EnableMongoRepositories
public class AppConfig extends AbstractMongoConfiguration { ... }

it just works fine.

I often have omitted @Configuration for the configuration class when it is explicit registered in the context (by classes in @ContextConfiguration or a register() method in AnnotationConfigWebApplicationContext). The classes were processed anyway and all declared beans are found. It is sometimes useful to not use @Configuration to prevent detecting by a component scan when there are 2 similar configuration classes in the same packages in a test context used by different tests. It generated an another question as I am not sure if it is a desired behavior.