Spring Boot DevTools on 5.1 fails with java.lang.LinkageError: loader attempted duplicate class definition [SPR-16902]

[spring-projects-issues]

Phil Webb opened SPR-16902 and commented

Spring Boot recently upgrade to Framework 5.1 SNAPSHOTS and we're now seeing "loader attempted duplicate class definition" errors with our devtools integration tests on Java 9 and Java 10 (Java 8 is fine).

Here's an example of a failing build.

Caused by: org.springframework.aop.framework.AopConfigException: Could not generate CGLIB subclass of class org.springframework.boot.autoconfigure.http.HttpMessageConverters: Common causes of this problem include using a final class or a non-visible class; nested exception is org.springframework.cglib.core.CodeGenerationException: java.lang.LinkageError-->loader (instance of  jdk/internal/loader/ClassLoaders$AppClassLoader): attempted  duplicate class definition for name: "org/springframework/boot/autoconfigure/http/HttpMessageConverters$$EnhancerBySpringCGLIB$$1d90bff9"
	at org.springframework.aop.framework.CglibAopProxy.getProxy(CglibAopProxy.java:208) ~[spring-aop-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.aop.framework.ProxyFactory.getProxy(ProxyFactory.java:110) ~[spring-aop-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.context.annotation.ContextAnnotationAutowireCandidateResolver.buildLazyResolutionProxy(ContextAnnotationAutowireCandidateResolver.java:117) ~[spring-context-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.context.annotation.ContextAnnotationAutowireCandidateResolver.getLazyResolutionProxyIfNecessary(ContextAnnotationAutowireCandidateResolver.java:52) ~[spring-context-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1062) ~[spring-beans-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:818) ~[spring-beans-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:724) ~[spring-beans-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:197) ~[spring-beans-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1276) ~[spring-beans-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1133) ~[spring-beans-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:543) ~[spring-beans-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:503) ~[spring-beans-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	... 34 common frames omitted
Caused by: org.springframework.cglib.core.CodeGenerationException: java.lang.LinkageError-->loader (instance of  jdk/internal/loader/ClassLoaders$AppClassLoader): attempted  duplicate class definition for name: "org/springframework/boot/autoconfigure/http/HttpMessageConverters$$EnhancerBySpringCGLIB$$1d90bff9"
	at org.springframework.cglib.core.ReflectUtils.defineClass(ReflectUtils.java:502) ~[spring-core-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.cglib.core.AbstractClassGenerator.generate(AbstractClassGenerator.java:359) ~[spring-core-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.cglib.proxy.Enhancer.generate(Enhancer.java:582) ~[spring-core-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:106) ~[spring-core-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:104) ~[spring-core-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.cglib.core.internal.LoadingCache$2.call(LoadingCache.java:54) ~[spring-core-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[na:na]
	at org.springframework.cglib.core.internal.LoadingCache.createEntry(LoadingCache.java:61) ~[spring-core-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.cglib.core.internal.LoadingCache.get(LoadingCache.java:34) ~[spring-core-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData.get(AbstractClassGenerator.java:130) ~[spring-core-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:315) ~[spring-core-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.cglib.proxy.Enhancer.createHelper(Enhancer.java:569) ~[spring-core-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.cglib.proxy.Enhancer.createClass(Enhancer.java:416) ~[spring-core-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.aop.framework.ObjenesisCglibAopProxy.createProxyClassAndInstance(ObjenesisCglibAopProxy.java:58) ~[spring-aop-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	at org.springframework.aop.framework.CglibAopProxy.getProxy(CglibAopProxy.java:205) ~[spring-aop-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	... 45 common frames omitted
Caused by: java.lang.LinkageError: loader (instance of  jdk/internal/loader/ClassLoaders$AppClassLoader): attempted  duplicate class definition for name: "org/springframework/boot/autoconfigure/http/HttpMessageConverters$$EnhancerBySpringCGLIB$$1d90bff9"
	at java.base/java.lang.ClassLoader.defineClass1(Native Method) ~[na:na]
	at java.base/java.lang.System$2.defineClass(System.java:2120) ~[na:na]
	at java.base/java.lang.invoke.MethodHandles$Lookup.defineClass(MethodHandles.java:964) ~[na:na]
	at java.base/jdk.internal.reflect.GeneratedMethodAccessor25.invoke(Unknown Source) ~[na:na]
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
	at java.base/java.lang.reflect.Method.invoke(Method.java:564) ~[na:na]
	at org.springframework.cglib.core.ReflectUtils.defineClass(ReflectUtils.java:498) ~[spring-core-5.1.0.BUILD-SNAPSHOT.jar:5.1.0.BUILD-SNAPSHOT]
	... 59 common frames omitted

The same tests on Spring Boot 2.0 (which uses Framework 5.0) pass fine on Java 8, 9 and 10.

My guess is this relates to #20414 and is probably caused by our slightly unusual DevTools classloader arrangement.

---

Affects: 5.1 RC1

Issue Links:

• MethodHandles.Lookup.defineClass for CGLIB class definition purposes [SPR-15859] #20414 MethodHandles.Lookup.defineClass for CGLIB class definition purposes
• Revise ClassUtils.isPresent for exposing resolution exceptions in jlinked modules [SPR-17018] #21556 Revise ClassUtils.isPresent for exposing resolution exceptions in jlinked modules

Referenced from: commits 6887802

[spring-projects-issues]

Juergen Hoeller commented

Since this is definitely a consequence of #20414 where we can't enforce the generation of a such a derived class into a specific ClassLoader, there is probably only one way out: keep using the old ClassLoader.defineClass approach for DevTools, even on JDK 9+. We already have a fallback for IllegalArgumentException coming out of the JDK 9 MethodHandles.Lookup API, so I guess we should simply fall back for LinkageError as well.

[spring-projects-issues]

Juergen Hoeller commented

We're falling back for IllegalArgumentException} (class in different package) as well as plain {{LinkageError (class already defined) now, matching the implementation of MethodHandles.Lookup.defineClass in JDK 9/10/11. We keep rethrowing all variants of LinkageError subclasses which typically indicate actual class definition issues.

This will be in the upcoming 5.1 snapshot. Please give it a try with DevTools and let me know how it goes...

[spring-projects-issues]

Andy Wilkinson commented

Thanks, Juergen. Boot 2.1's build is now passing on both Java 9 and Java 10.