sb3cce

Demo app to reproduce ClassCastException on beanFactory race condition

How to reproduce

• Build it: mvn clean package
• Run it: ./runForver.sh | grep java.lang.ClassCastException

What is happening

Spring will fail eventually with:

Exception in thread "Thread-2" java.lang.ClassCastException: class java.lang.Class cannot be cast to class java.lang.String (java.lang.Class and java.lang.String are in module java.base of loader 'bootstrap')
        at org.springframework.beans.factory.support.AbstractBeanDefinition.getBeanClassName(AbstractBeanDefinition.java:393)
        at org.springframework.beans.factory.support.AbstractBeanFactory.doResolveBeanClass(AbstractBeanFactory.java:1535)
        at org.springframework.beans.factory.support.AbstractBeanFactory.resolveBeanClass(AbstractBeanFactory.java:1502)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:492)
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:344)
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:225)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveNamedBean(DefaultListableBeanFactory.java:1310)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveNamedBean(DefaultListableBeanFactory.java:1271)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveBean(DefaultListableBeanFactory.java:484)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBean(DefaultListableBeanFactory.java:339)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBean(DefaultListableBeanFactory.java:332)
....

Analyzes so far

This bug is reproducable in Spring-Boot-Versions 3.0.3 till 3.0.8 and even 3.1.1.

This Bug will not happen in versions prior to 3.

What the demo does

The app starts several threads all accessing the beanFactory the get the same bean.