Exception retrieving empty Set from mongodb database

[francadaval]

I have an entity bean like this:

@Document
public class AccountData implements Serializable
{
	@Id
	private String userId;
	private String description;
	private Date birthday;
	private Set<Occupation> occupations;
	// Other simple attributes

	// Getters and setters
}

When I add Occupation items to Set, those are serialized and deserialized from database without any problem.

But when the Set is empty and I try to retrieve it from database I get this exception:

java.lang.IllegalArgumentException: Can not set java.util.Set field org.myproject.data.beans.AccountData.occupations to java.util.LinkedList
	at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:146)
	at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:150)
	at sun.reflect.UnsafeObjectFieldAccessorImpl.set(UnsafeObjectFieldAccessorImpl.java:63)
	at java.lang.reflect.Field.set(Field.java:657)
	at org.springframework.util.ReflectionUtils.setField(ReflectionUtils.java:92)
	at org.springframework.data.mapping.BeanWrapper.setProperty(BeanWrapper.java:159)
	at org.springframework.data.document.mongodb.convert.MappingMongoConverter$2.doWithPersistentProperty(MappingMongoConverter.java:242)
	at org.springframework.data.document.mongodb.convert.MappingMongoConverter$2.doWithPersistentProperty(MappingMongoConverter.java:230)
	at org.springframework.data.mapping.BasicPersistentEntity.doWithProperties(BasicPersistentEntity.java:112)
	at org.springframework.data.document.mongodb.convert.MappingMongoConverter.read(MappingMongoConverter.java:230)
	at org.springframework.data.document.mongodb.convert.MappingMongoConverter.read(MappingMongoConverter.java:174)
	at org.springframework.data.document.mongodb.convert.MappingMongoConverter.read(MappingMongoConverter.java:128)
	at org.springframework.data.document.mongodb.MongoTemplate$ReadDbObjectCallback.doWith(MongoTemplate.java:1655)
	at org.springframework.data.document.mongodb.MongoTemplate.executeFindOneInternal(MongoTemplate.java:1374)
	at org.springframework.data.document.mongodb.MongoTemplate.doFindOne(MongoTemplate.java:1145)
	at org.springframework.data.document.mongodb.MongoTemplate.findById(MongoTemplate.java:608)
	at org.springframework.data.document.mongodb.MongoTemplate.findById(MongoTemplate.java:600)
	at org.springframework.data.document.mongodb.repository.SimpleMongoRepository.findOne(SimpleMongoRepository.java:104)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.springframework.data.repository.support.RepositoryFactorySupport$QueryExecuterMethodInterceptor.executeMethodOn(RepositoryFactorySupport.java:358)
	at org.springframework.data.repository.support.RepositoryFactorySupport$QueryExecuterMethodInterceptor.invoke(RepositoryFactorySupport.java:339)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
	at $Proxy20.findOne(Unknown Source)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:309)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
	at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:89)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
	at $Proxy22.findOne(Unknown Source)
	at org.myproject.data.services.impl.UserServiceImpl.getAccountData(UserServiceImpl.java:158)
	...

[francadaval]

I've seen Oliver Gierke has created a Jira issue for this error (https://jira.springsource.org/browse/DATADOC-192).

I'm not familiar with Springsource Jira. Must I report directly to Jira when I think I've found an unknown bug?

Thank you.

PD.- Oliver I'll try to reproduce the error reported by me in stackoverflow and send de stacktrace. I have had no time for this one.

[Oliver Gierke]

It's already fixed . See [0] for the commit. I am just publishing the build to the snapshot repo.

[0] https://github.com/SpringSource/spri...4e0a7f0b142855