Spring-cloud-sleuth: No visible constructors in class java.util.concurrent.Executors$DelegatedScheduledExecutorService

[FlorianLautenschlager]

Tested versions:

• 1.2.1 and 1.2.4 (Workaround see below)

How to reproduce:

The bean

@Bean
public ScheduledExecutorService scheduledExecutorService() {
        return Executors.newSingleThreadScheduledExecutor();
}

leads to an java.lang.IllegalArgumentException: No visible constructors in class exception as Sleuth tries to wrap the Executor bean in ExecutorBeanPostProcessor.java. As Executors.newSingleThreadScheduledExecutor() does not have a public constructor its the expected behavior.

Here is the stacktrace:

Caused by: org.springframework.aop.framework.AopConfigException: Could not generate CGLIB subclass of class [class java.util.concurrent.Executors$DelegatedScheduledExecutorService]: Common causes of this problem include using a final class or a non-visible class; nested exception is java.lang.IllegalArgumentException: No visible constructors in class java.util.concurrent.Executors$DelegatedScheduledExecutorService
    at org.springframework.aop.framework.CglibAopProxy.getProxy(CglibAopProxy.java:211)
    at org.springframework.aop.framework.ProxyFactoryBean.getProxy(ProxyFactoryBean.java:368)
    at org.springframework.aop.framework.ProxyFactoryBean.getSingletonInstance(ProxyFactoryBean.java:322)
    at org.springframework.aop.framework.ProxyFactoryBean.getObject(ProxyFactoryBean.java:246)
    at org.springframework.cloud.sleuth.instrument.async.ExecutorBeanPostProcessor.postProcessAfterInitialization(ExecutorBeanPostProcessor.java:67)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsAfterInitialization(AbstractAutowireCapableBeanFactory.java:423)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1633)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555)
    ... 23 common frames omitted
Caused by: java.lang.IllegalArgumentException: No visible constructors in class java.util.concurrent.Executors$DelegatedScheduledExecutorService
    at org.springframework.cglib.proxy.Enhancer.filterConstructors(Enhancer.java:666)
    at org.springframework.cglib.proxy.Enhancer.generateClass(Enhancer.java:567)
    at org.springframework.cglib.transform.TransformingClassGenerator.generateClass(TransformingClassGenerator.java:33)
    at org.springframework.cglib.core.DefaultGeneratorStrategy.generate(DefaultGeneratorStrategy.java:25)
    at org.springframework.aop.framework.CglibAopProxy$ClassLoaderAwareUndeclaredThrowableStrategy.generate(CglibAopProxy.java:999)
    at org.springframework.cglib.core.AbstractClassGenerator.generate(AbstractClassGenerator.java:329)
    at org.springframework.cglib.proxy.Enhancer.generate(Enhancer.java:492)
    at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:93)
    at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:91)
    at org.springframework.cglib.core.internal.LoadingCache$2.call(LoadingCache.java:54)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at org.springframework.cglib.core.internal.LoadingCache.createEntry(LoadingCache.java:61)
    at org.springframework.cglib.core.internal.LoadingCache.get(LoadingCache.java:34)
    at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData.get(AbstractClassGenerator.java:116)
    at org.springframework.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:291)
    at org.springframework.cglib.proxy.Enhancer.createHelper(Enhancer.java:480)
    at org.springframework.cglib.proxy.Enhancer.createClass(Enhancer.java:337)
    at org.springframework.aop.framework.ObjenesisCglibAopProxy.createProxyClassAndInstance(ObjenesisCglibAopProxy.java:55)
    at org.springframework.aop.framework.CglibAopProxy.getProxy(CglibAopProxy.java:201)
    ... 30 common frames omitted

Workaround

public ScheduledExecutorService scheduledExecutorService() {
        return Executors.newScheduledThreadPool(1);
 }

[FlorianLautenschlager]

Yeah. :1st_place_medal: