MongoDB Batch Job Broken in Spring XD 1.2.0+ - spring

Question

We have a batch job running in Spring XD which reads from MongoDB using the standard MongoItemReader which converts mongo records to our domain model. Up to Spring XD version 1.1.3 this worked fine, however in versions 1.2.0 and 1.2.1 the job is failing with the following error (package name shortened)
java.lang.NoClassDefFoundError: c/s/r/b/b/domain/IndexId
at c.s.r.b.b.domain.IndexId_Instantiator_hxmj4p.newInstance(Unknown Source) ~[na:na]
at
org.springframework.data.convert.BytecodeGeneratingEntityInstantiator$EntityInstantiatorAdapter.createInstance(BytecodeGeneratingEntityInstantiator.java:193) ~
[spring-data-commons-1.10.0.RELEASE.jar:na]
at org.springframework.data.convert.BytecodeGeneratingEntityInstantiator.createInstance
(BytecodeGeneratingEntityInstantiator.java:76) ~[spring-data-commons-1.10.0.RELEASE.jar:na]
at
org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:250) ~[spring-data-mongodb-1.7.0.RELEASE.jar:na]
at
org.springframework.data.mongodb.core.convert.MappingMongoConverter.read(MappingMongoConverter.java:231) ~[spring-data-mongodb-1.7.0.RELEASE.jar:na]
Looking into this I found the threads NoClassDefFoundError when making a query in spring-data-solr within a play framework application, and NoClassDefFoundError after upgrading to 1.7.0.RELEASE which suggest this is due to a change in spring-data-mongo 1.7.0 and the underlying spring-data-commons to change the default entity instantiation technique to improve performance.
Based on the suggested fix in those threads I've modified the mongo template in my job module XML definition as follows and this fixes the problem:
<bean id="mappingConverter" class="org.springframework.data.mongodb.core.convert.MappingMongoConverter">
<constructor-arg ref="dbRefResolver"/>
<constructor-arg ref="mongoMappingContext"/>
<property name="instantiators" ref="entityInstantiators" />
</bean>
<bean id="dbRefResolver" class="org.springframework.data.mongodb.core.convert.DefaultDbRefResolver">
<constructor-arg ref="mongoDbFactory"/>
</bean>
<bean id="mongoMappingContext" class="org.springframework.data.mongodb.core.mapping.MongoMappingContext"/>
<bean id="entityInstantiators" class="org.springframework.data.convert.EntityInstantiators">
<constructor-arg value="#{T(org.springframework.data.convert.ReflectionEntityInstantiator).INSTANCE}"/>
</bean>
<bean id="mongoTemplate" class="org.springframework.data.mongodb.core.MongoTemplate">
<constructor-arg name="mongoDbFactory" ref="mongoDbFactory" />
<constructor-arg name="mongoConverter" ref="mappingConverter" />
</bean>
However this is verbose and obviously isn't an ideal fix. The problem doesn't show up in our job module integration test so I have a hunch its caused by a combination of the default entity instantiation change and the fact that when a module executes in Spring XD the domain classes will be in the module's class loader and not visible to the spring data mongo classes in XD's main class loader.
So should this be regarded as a bug in Spring XD or Spring Data Mongo? One fix might be an improvement to the Spring Data Mongo mongo:mapping-converter XML configuration to allow forcing the use of the ReflectionEntityInstantiator which would at least reduce the amount of XML needed above. Alternatively maybe Spring XD should handle this scenario automatically?

Answer 1

I don't think there is anything we can do from the XD side since this is a custom job. We have to rely on the spring-data-mongodb functionality.

Answer 2

It looks like you're running into DATACMNS-710, which is fixed in Fowler SR1 (equivalent to Spring Data MongoDB 1.7.1). You might wanna try the just released Gosling release, too.