NullPointerException during AOT processing when MongoDB domain model

[ckdgus08]

Hello,

First of all, thank you for your continued work on the Spring ecosystem.
I encountered a NullPointerException while using Spring Boot 3.4.5 with AOT processing enabled, and I'd like to report a potential bug.

Based on my debugging, it seems that a NullPointerException occurs when using Jackson with Mongo data models annotated with @ Document.

If this issue is not already being worked on, I would like to submit a pull request with a fix.

Environment

• Spring Boot: 3.4.5
• Spring Data MongoDB
• GraalVM / Native AOT enabled

Stack Trace

Exception in thread "main" org.springframework.beans.factory.aot.AotBeanProcessingException: Error processing bean with name 'mongoManagedTypes' defined in class path resource [org/springframework/boot/autoconfigure/data/mongo/MongoDataConfiguration.class]: failed to generate code for bean definition
	at org.springframework.beans.factory.aot.BeanRegistrationsAotContribution$BeanDefinitionsRegistrationGenerator.lambda$generateRegisterBeanDefinitionMethods$2(BeanRegistrationsAotContribution.java:217)
	at java.base/java.lang.Iterable.forEach(Iterable.java:75)
	at org.springframework.beans.factory.aot.BeanRegistrationsAotContribution$BeanDefinitionsRegistrationGenerator.generateRegisterBeanDefinitionMethods(BeanRegistrationsAotContribution.java:207)
	at org.springframework.beans.factory.aot.BeanRegistrationsAotContribution$BeanDefinitionsRegistrationGenerator.lambda$generateSliceMethod$1(BeanRegistrationsAotContribution.java:198)
	at org.springframework.aot.generate.GeneratedMethod.<init>(GeneratedMethod.java:54)
	at org.springframework.aot.generate.GeneratedMethods.add(GeneratedMethods.java:112)
	at org.springframework.aot.generate.GeneratedMethods.add(GeneratedMethods.java:89)
	at org.springframework.beans.factory.aot.BeanRegistrationsAotContribution$BeanDefinitionsRegistrationGenerator.generateSliceMethod(BeanRegistrationsAotContribution.java:194)
	at org.springframework.beans.factory.aot.BeanRegistrationsAotContribution$BeanDefinitionsRegistrationGenerator.lambda$generateRegisterBeanDefinitionsMethod$0(BeanRegistrationsAotContribution.java:181)
	at org.springframework.aot.generate.GeneratedMethod.<init>(GeneratedMethod.java:54)
	at org.springframework.aot.generate.GeneratedMethods.add(GeneratedMethods.java:112)
	at org.springframework.aot.generate.GeneratedMethods.add(GeneratedMethods.java:89)
	at org.springframework.beans.factory.aot.BeanRegistrationsAotContribution$BeanDefinitionsRegistrationGenerator.generateRegisterBeanDefinitionsMethod(BeanRegistrationsAotContribution.java:166)
	at org.springframework.beans.factory.aot.BeanRegistrationsAotContribution.applyTo(BeanRegistrationsAotContribution.java:77)
	at org.springframework.context.aot.BeanFactoryInitializationAotContributions.applyTo(BeanFactoryInitializationAotContributions.java:96)
	at org.springframework.context.aot.ApplicationContextAotGenerator.lambda$processAheadOfTime$0(ApplicationContextAotGenerator.java:58)
	at org.springframework.context.aot.ApplicationContextAotGenerator.withCglibClassHandler(ApplicationContextAotGenerator.java:67)
	at org.springframework.context.aot.ApplicationContextAotGenerator.processAheadOfTime(ApplicationContextAotGenerator.java:53)
	at org.springframework.context.aot.ContextAotProcessor.performAotProcessing(ContextAotProcessor.java:106)
	at org.springframework.context.aot.ContextAotProcessor.doProcess(ContextAotProcessor.java:84)
	at org.springframework.context.aot.ContextAotProcessor.doProcess(ContextAotProcessor.java:49)
	at org.springframework.context.aot.AbstractAotProcessor.process(AbstractAotProcessor.java:83)
	at org.springframework.boot.SpringApplicationAotProcessor.main(SpringApplicationAotProcessor.java:80)
Caused by: java.lang.NullPointerException: Cannot invoke "java.lang.Package.getName()" because the return value of "java.lang.Class.getPackage()" is null
Caused by: java.lang.NullPointerException: Cannot invoke "java.lang.Package.getName()" because the return value of "java.lang.Class.getPackage()" is null

	at org.springframework.data.util.QTypeContributor.getQueryClassName(QTypeContributor.java:83)
	at org.springframework.data.util.QTypeContributor.contributeEntityPath(QTypeContributor.java:44)
	at org.springframework.data.aot.ManagedTypesBeanRegistrationAotProcessor.contributeType(ManagedTypesBeanRegistrationAotProcessor.java:140)
	at org.springframework.data.mongodb.aot.MongoManagedTypesBeanRegistrationAotProcessor.contributeType(MongoManagedTypesBeanRegistrationAotProcessor.java:53)
	at org.springframework.data.aot.ManagedTypesRegistrationAotContribution.lambda$applyTo$0(ManagedTypesRegistrationAotContribution.java:96)
	at org.springframework.data.util.TypeCollector.processType(TypeCollector.java:103)
	at org.springframework.data.util.TypeCollector.processType(TypeCollector.java:117)
	at org.springframework.data.util.TypeCollector.processType(TypeCollector.java:117)
	at org.springframework.data.util.TypeCollector.processType(TypeCollector.java:117)
	at org.springframework.data.util.TypeCollector.processType(TypeCollector.java:117)
	at org.springframework.data.util.TypeCollector.processType(TypeCollector.java:117)
	at org.springframework.data.util.TypeCollector.processType(TypeCollector.java:117)
	at org.springframework.data.util.TypeCollector.processType(TypeCollector.java:117)
	at org.springframework.data.util.TypeCollector.processType(TypeCollector.java:117)
	at org.springframework.data.util.TypeCollector.processType(TypeCollector.java:117)
	at org.springframework.data.util.TypeCollector.processType(TypeCollector.java:117)
	at org.springframework.data.util.TypeCollector.process(TypeCollector.java:90)
	at org.springframework.data.util.TypeCollector$ReachableTypes.lambda$forEach$0(TypeCollector.java:229)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1596)
	at org.springframework.data.util.TypeCollector$ReachableTypes.forEach(TypeCollector.java:229)
	at org.springframework.data.aot.ManagedTypesRegistrationAotContribution.applyTo(ManagedTypesRegistrationAotContribution.java:96)
	at org.springframework.beans.factory.aot.BeanDefinitionMethodGenerator.lambda$generateBeanDefinitionMethod$2(BeanDefinitionMethodGenerator.java:165)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1596)
	at org.springframework.beans.factory.aot.BeanDefinitionMethodGenerator.generateBeanDefinitionMethod(BeanDefinitionMethodGenerator.java:165)
	at org.springframework.beans.factory.aot.BeanDefinitionMethodGenerator.generateBeanDefinitionMethod(BeanDefinitionMethodGenerator.java:89)
	at org.springframework.beans.factory.aot.BeanRegistrationsAotContribution$BeanDefinitionsRegistrationGenerator.generateBeanRegistration(BeanRegistrationsAotContribution.java:226)
	at org.springframework.beans.factory.aot.BeanRegistrationsAotContribution$BeanDefinitionsRegistrationGenerator.lambda$generateRegisterBeanDefinitionMethods$2(BeanRegistrationsAotContribution.java:209)
	... 22 more

[christophstrobl]

Thank you for reporting! Please help us diagnose the issue by providing a complete minimal sample (something that we can unzip or git clone, build, and deploy) that reproduces the problem. Right now I do not see the Jackson & MongoDB connection but some Q class resolution failure for Querydsl generated types.

[ckdgus08]

I’ve created a minimal project that reproduces the issue. You can find it here:

🔗 https://github.com/ckdgus08/demo-aot-npe

It uses Spring Boot with AOT enabled and includes Querydsl and MongoDB dependencies.

The issue occurs during the AOT processing phase while generating metadata for the Querydsl-generated Q classes. Specifically, it seems to be triggered when Jackson-related code is being processed—possibly during introspection or serialization configuration. This causes the AOT engine to fail when trying to handle the generated Querydsl types.

Please let me know if there’s anything I can improve or clarify further. Thanks again for taking a look!