Spring Modulith Observability NPE when method has a wildcard parameter

[sfilipiak-inpost]

Issue:

When using Spring Modulith Observability and calling cross module method which has a wildcard <?> generic parameter NPE is thrown.

2026-07-10T09:45:37.777+02:00 ERROR 9648 --- [spring-modulith-observability-npe] [           main] [                                                 ] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'component1': Invocation of init method failed
	at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:220) ~[spring-beans-7.0.8.jar:7.0.8]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:426) ~[spring-beans-7.0.8.jar:7.0.8]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1807) ~[spring-beans-7.0.8.jar:7.0.8]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:603) ~[spring-beans-7.0.8.jar:7.0.8]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:525) ~[spring-beans-7.0.8.jar:7.0.8]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:333) ~[spring-beans-7.0.8.jar:7.0.8]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:371) ~[spring-beans-7.0.8.jar:7.0.8]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:331) ~[spring-beans-7.0.8.jar:7.0.8]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:196) ~[spring-beans-7.0.8.jar:7.0.8]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.instantiateSingleton(DefaultListableBeanFactory.java:1225) ~[spring-beans-7.0.8.jar:7.0.8]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingleton(DefaultListableBeanFactory.java:1191) ~[spring-beans-7.0.8.jar:7.0.8]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:1121) ~[spring-beans-7.0.8.jar:7.0.8]
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:994) ~[spring-context-7.0.8.jar:7.0.8]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:621) ~[spring-context-7.0.8.jar:7.0.8]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:756) ~[spring-boot-4.1.0.jar:4.1.0]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:445) ~[spring-boot-4.1.0.jar:4.1.0]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:321) ~[spring-boot-4.1.0.jar:4.1.0]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1365) ~[spring-boot-4.1.0.jar:4.1.0]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1354) ~[spring-boot-4.1.0.jar:4.1.0]
	at com.montes.springmodulithobservabilitynpe.SpringModulithObservabilityNpeApplication.main(SpringModulithObservabilityNpeApplication.java:10) ~[classes/:na]
Caused by: java.lang.NullPointerException: Cannot invoke "java.lang.Class.getTypeName()" because "type" is null
	at org.springframework.modulith.core.FormattableType.of(FormattableType.java:108) ~[spring-modulith-core-2.1.0.jar:2.1.0]
	at org.springframework.modulith.observability.support.DefaultObservedModule.render(DefaultObservedModule.java:129) ~[spring-modulith-observability-core-2.1.0.jar:2.1.0]
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:214) ~[na:na]
	at java.base/java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:1024) ~[na:na]
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:570) ~[na:na]
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:560) ~[na:na]
	at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:921) ~[na:na]
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:265) ~[na:na]
	at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:723) ~[na:na]
	at org.springframework.modulith.observability.support.DefaultObservedModule.render(DefaultObservedModule.java:138) ~[spring-modulith-observability-core-2.1.0.jar:2.1.0]
	at org.springframework.modulith.observability.support.DefaultObservedModule.lambda$format$0(DefaultObservedModule.java:118) ~[spring-modulith-observability-core-2.1.0.jar:2.1.0]
	at java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1724) ~[na:na]
	at org.springframework.modulith.observability.support.DefaultObservedModule.format(DefaultObservedModule.java:106) ~[spring-modulith-observability-core-2.1.0.jar:2.1.0]
	at org.springframework.modulith.observability.support.ModuleEntryInterceptor.invoke(ModuleEntryInterceptor.java:110) ~[spring-modulith-observability-core-2.1.0.jar:2.1.0]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-7.0.8.jar:7.0.8]
	at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:719) ~[spring-aop-7.0.8.jar:7.0.8]
	at com.montes.springmodulithobservabilitynpe.module2.Component2$$SpringCGLIB$$0.method(<generated>) ~[classes/:na]
	at com.montes.springmodulithobservabilitynpe.module1.Component1.init(Component1.java:16) ~[classes/:na]
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104) ~[na:na]
	at java.base/java.lang.reflect.Method.invoke(Method.java:565) ~[na:na]
	at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMethod.invoke(InitDestroyAnnotationBeanPostProcessor.java:453) ~[spring-beans-7.0.8.jar:7.0.8]
	at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMetadata.invokeInitMethods(InitDestroyAnnotationBeanPostProcessor.java:397) ~[spring-beans-7.0.8.jar:7.0.8]
	at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:217) ~[spring-beans-7.0.8.jar:7.0.8]
	... 19 common frames omitted

Steps to reproduce:

Spring Boot: 4.1.0
Spring Modulith: 2.1.0
Dependencies:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-opentelemetry</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.modulith</groupId>
    <artifactId>spring-modulith-observability-api</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.modulith</groupId>
    <artifactId>spring-modulith-starter-core</artifactId>
</dependency>

<dependency>
    <groupId>org.springframework.modulith</groupId>
    <artifactId>spring-modulith-observability-core</artifactId>
    <scope>runtime</scope>
</dependency>
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <optional>true</optional>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-opentelemetry-test</artifactId>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>org.springframework.modulith</groupId>
    <artifactId>spring-modulith-starter-test</artifactId>
    <scope>test</scope>
</dependency>

Component1 in module1

package com.montes.springmodulithobservabilitynpe.module1;

import com.montes.springmodulithobservabilitynpe.module2.Component2;
import jakarta.annotation.PostConstruct;
import lombok.RequiredArgsConstructor;
import org.springframework.stereotype.Component;

@Component
@RequiredArgsConstructor
public class Component1 {

    private final Component2 component2;

    @PostConstruct
    public void init() {
        component2.method(Component1.class);
    }

}

Component2 in module2

package com.montes.springmodulithobservabilitynpe.module2;

import org.springframework.stereotype.Component;

@Component
public class Component2 {

    public void method(Class<?> clazz) {}

}