在实际开发过中遇到过2次，此问题隐藏的比较深。
main线程在启动时，做Ioc容器初始化操作，如果应用中涉及到大量的Bean初始化，这个过程比较耗时。
此时，你的应用有个地方在起了个线程，该线程执行了一些类似application.getBean(xxx)的操作，就有可能发送deadlock.
本质原因：IOC容器维护了两个map，分别是BeanDefinitionMap和SingletonObjectMap。前者是bean定义的元数据信息，bean的实例化是基于该元数据创建的。如果创建的时单例，则会放入singletonObjectMap中。
main线程的加锁顺序：先BeanDefinitionMap后SingletonObjectMap ；子线程是获取bean是先SingletonObjectMap后BeanDefinitionMap。这个过程会发生死锁。
示例：堆栈信息
Thread Name: main
Waited Count: 9 Waited Time: -1ms
Blocked Count: 332 Blocked Time: -1ms
Lock Name: java.lang.Object@34e911de Lock Class Name: java.lang.Object Lock Identity Hash Code: 887689694
Waiting for lock owned by 86 Owner Name: datacollect-1
Locked Monitors
Frame: 21 org.springframework.beans.factory.support.DefaultSingletonBeanRegistry . getSingleton (DefaultSingletonBeanRegistry.java)
Frame: 35 org.springframework.beans.factory.support.DefaultSingletonBeanRegistry . getSingleton (DefaultSingletonBeanRegistry.java)
Frame: 40 org.springframework.context.support.AbstractApplicationContext . refresh (AbstractApplicationContext.java)
Stack Trace
org.springframework.amqp.rabbit.connection.CachingConnectionFactory . createConnection (CachingConnectionFactory.java:626)
org.springframework.amqp.rabbit.connection.ConnectionFactoryUtils . createConnection (ConnectionFactoryUtils.java:240)
org.springframework.amqp.rabbit.core.RabbitTemplate . doExecute (RabbitTemplate.java:1816)
org.springframework.amqp.rabbit.core.RabbitTemplate . execute (RabbitTemplate.java:1790)
org.springframework.amqp.rabbit.core.RabbitTemplate . execute (RabbitTemplate.java:1771)
cn.caijiajia.magic.realtimecompute.connector.rabbit.bind.AbstractRabbitExchangeBind . queueBind (AbstractRabbitExchangeBind.java:70)
cn.caijiajia.magic.realtimecompute.connector.rabbit.bind.AsyncRabbitExchangeBind . synExchange (AsyncRabbitExchangeBind.java:76)
cn.caijiajia.magic.realtimecompute.connector.rabbit.bind.AsyncRabbitExchangeBind . asyncInitRabbit (AsyncRabbitExchangeBind.java:68)
sun.reflect.NativeMethodAccessorImpl . invoke0 (NativeMethodAccessorImpl.java) (Native)
sun.reflect.NativeMethodAccessorImpl . invoke (NativeMethodAccessorImpl.java:62)
sun.reflect.DelegatingMethodAccessorImpl . invoke (DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method . invoke (Method.java:498)
org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleElement . invoke (InitDestroyAnnotationBeanPostProcessor.java:366)
org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMetadata . invokeInitMethods (InitDestroyAnnotationBeanPostProcessor.java:309)
org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor . postProcessBeforeInitialization (InitDestroyAnnotationBeanPostProcessor.java:136)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory . applyBeanPostProcessorsBeforeInitialization (AbstractAutowireCapableBeanFactory.java:416)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory . initializeBean (AbstractAutowireCapableBeanFactory.java:1686)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory . doCreateBean (AbstractAutowireCapableBeanFactory.java:573)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory . createBean (AbstractAutowireCapableBeanFactory.java:495)
org.springframework.beans.factory.support.AbstractBeanFactory . lambda$doGetBean$0 (AbstractBeanFactory.java:317)
org.springframework.beans.factory.support.AbstractBeanFactory$$Lambda$168/1906808037 . getObject ()
org.springframework.beans.factory.support.DefaultSingletonBeanRegistry . getSingleton (DefaultSingletonBeanRegistry.java:222)
org.springframework.beans.factory.support.AbstractBeanFactory . doGetBean (AbstractBeanFactory.java:315)
org.springframework.beans.factory.support.AbstractBeanFactory . getBean (AbstractBeanFactory.java:204)
org.springframework.context.annotation.CommonAnnotationBeanPostProcessor . autowireResource (CommonAnnotationBeanPostProcessor.java:514)
org.springframework.context.annotation.CommonAnnotationBeanPostProcessor . getResource (CommonAnnotationBeanPostProcessor.java:485)
org.springframework.context.annotation.CommonAnnotationBeanPostProcessor$ResourceElement . getResourceToInject (CommonAnnotationBeanPostProcessor.java:619)
org.springframework.beans.factory.annotation.InjectionMetadata$InjectedElement . inject (InjectionMetadata.java:180)
org.springframework.beans.factory.annotation.InjectionMetadata . inject (InjectionMetadata.java:90)
org.springframework.context.annotation.CommonAnnotationBeanPostProcessor . postProcessPropertyValues (CommonAnnotationBeanPostProcessor.java:318)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory . populateBean (AbstractAutowireCapableBeanFactory.java:1336)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory . doCreateBean (AbstractAutowireCapableBeanFactory.java:572)
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory . createBean (AbstractAutowireCapableBeanFactory.java:495)
org.springframework.beans.factory.support.AbstractBeanFactory . lambda$doGetBean$0 (AbstractBeanFactory.java:317)
org.springframework.beans.factory.support.AbstractBeanFactory$$Lambda$168/1906808037 . getObject ()
org.springframework.beans.factory.support.DefaultSingletonBeanRegistry . getSingleton (DefaultSingletonBeanRegistry.java:222)
org.springframework.beans.factory.support.AbstractBeanFactory . doGetBean (AbstractBeanFactory.java:315)
org.springframework.beans.factory.support.AbstractBeanFactory . getBean (AbstractBeanFactory.java:199)
org.springframework.beans.factory.support.DefaultListableBeanFactory . preInstantiateSingletons (DefaultListableBeanFactory.java:759)
org.springframework.context.support.AbstractApplicationContext . finishBeanFactoryInitialization (AbstractApplicationContext.java:867)
org.springframework.context.support.AbstractApplicationContext . refresh (AbstractApplicationContext.java:548)
org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext . refresh (ServletWebServerApplicationContext.java:140)
org.springframework.boot.SpringApplication . refresh (SpringApplication.java:754)
org.springframework.boot.SpringApplication . refreshContext (SpringApplication.java:386)
org.springframework.boot.SpringApplication . run (SpringApplication.java:307)
org.springframework.boot.SpringApplication . run (SpringApplication.java:1242)
org.springframework.boot.SpringApplication . run (SpringApplication.java:1230)
cn.caijiajia.magic.realtimecompute.RealtimeApplication . main (RealtimeApplication.java:31)
sun.reflect.NativeMethodAccessorImpl . invoke0 (NativeMethodAccessorImpl.java) (Native)
sun.reflect.NativeMethodAccessorImpl . invoke (NativeMethodAccessorImpl.java:62)
sun.reflect.DelegatingMethodAccessorImpl . invoke (DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method . invoke (Method.java:498)
org.springframework.boot.loader.MainMethodRunner . run (MainMethodRunner.java:48)
org.springframework.boot.loader.Launcher . launch (Launcher.java:87)
org.springframework.boot.loader.Launcher . launch (Launcher.java:50)
org.springframework.boot.loader.JarLauncher . main (JarLauncher.java:51)
--------------------------------------------------------------------------------
Thread Name: datacollect-1
Waited Count: 3 Waited Time: -1ms
Blocked Count: 13 Blocked Time: -1ms
Lock Name: java.util.concurrent.ConcurrentHashMap@1b841c8 Lock Class Name: java.util.concurrent.ConcurrentHashMap Lock Identity Hash Code: 28852680
Waiting for lock owned by 1 Owner Name: main
Locked Synchronizers
Class Name: java.util.concurrent.ThreadPoolExecutor$Worker Identity Hash Code: 1810349933
Locked Monitors
Frame: 15 org.springframework.amqp.rabbit.connection.CachingConnectionFactory . createConnection (CachingConnectionFactory.java)
Stack Trace
org.springframework.beans.factory.support.DefaultSingletonBeanRegistry . getSingleton (DefaultSingletonBeanRegistry.java:179)
org.springframework.beans.factory.support.AbstractBeanFactory . isTypeMatch (AbstractBeanFactory.java:490)
org.springframework.beans.factory.support.DefaultListableBeanFactory . doGetBeanNamesForType (DefaultListableBeanFactory.java:426)
org.springframework.beans.factory.support.DefaultListableBeanFactory . getBeanNamesForType (DefaultListableBeanFactory.java:397)
org.springframework.beans.factory.support.DefaultListableBeanFactory . getBeansOfType (DefaultListableBeanFactory.java:510)
org.springframework.beans.factory.support.DefaultListableBeanFactory . getBeansOfType (DefaultListableBeanFactory.java:502)
org.springframework.context.support.AbstractApplicationContext . getBeansOfType (AbstractApplicationContext.java:1196)
org.springframework.amqp.rabbit.core.RabbitAdmin . initialize (RabbitAdmin.java:485)
org.springframework.amqp.rabbit.core.RabbitAdmin . lambda$null$9 (RabbitAdmin.java:453)
org.springframework.amqp.rabbit.core.RabbitAdmin$$Lambda$594/1637332799 . doWithRetry ()
org.springframework.retry.support.RetryTemplate . doExecute (RetryTemplate.java:287)
org.springframework.retry.support.RetryTemplate . execute (RetryTemplate.java:164)
org.springframework.amqp.rabbit.core.RabbitAdmin . lambda$afterPropertiesSet$10 (RabbitAdmin.java:452)
org.springframework.amqp.rabbit.core.RabbitAdmin$$Lambda$591/256139608 . onCreate ()
org.springframework.amqp.rabbit.connection.CompositeConnectionListener . onCreate (CompositeConnectionListener.java:36)
org.springframework.amqp.rabbit.connection.CachingConnectionFactory . createConnection (CachingConnectionFactory.java:634)
org.springframework.amqp.rabbit.connection.ConnectionFactoryUtils . createConnection (ConnectionFactoryUtils.java:240)
cn.caijiajia.rabbitmq.client.CjjRabbitTemplate . doExecute (CjjRabbitTemplate.java:1467)
cn.caijiajia.rabbitmq.client.CjjRabbitTemplate . access$300 (CjjRabbitTemplate.java:121)
cn.caijiajia.rabbitmq.client.CjjRabbitTemplate$3 . doWithRetry (CjjRabbitTemplate.java:1420)
org.springframework.retry.support.RetryTemplate . doExecute (RetryTemplate.java:287)
org.springframework.retry.support.RetryTemplate . execute (RetryTemplate.java:180)
cn.caijiajia.rabbitmq.client.CjjRabbitTemplate . execute (CjjRabbitTemplate.java:1411)
cn.caijiajia.rabbitmq.client.CjjRabbitTemplate . sendme (CjjRabbitTemplate.java:535)
cn.caijiajia.rabbitmq.client.CjjRabbitTemplate . sendTwice (CjjRabbitTemplate.java:527)
cn.caijiajia.rabbitmq.client.CjjRabbitTemplate . send (CjjRabbitTemplate.java:513)
cn.caijiajia.rabbitmq.client.CjjRabbitTemplate . convertAndSend (CjjRabbitTemplate.java:628)
cn.caijiajia.rabbitmq.client.CjjRabbitTemplate . convertAndSend (CjjRabbitTemplate.java:623)
cn.caijiajia.traceplus.starter.collector.reporter.RabbitmqReporter . report (RabbitmqReporter.java:46)
cn.caijiajia.traceplus.starter.collector.AbstractDataCollector . syncReport (AbstractDataCollector.java:143)
cn.caijiajia.traceplus.starter.collector.AbstractDataCollector . lambda$asyncReport$0 (AbstractDataCollector.java:120)
cn.caijiajia.traceplus.starter.collector.AbstractDataCollector$$Lambda$582/962927234 . run ()
java.util.concurrent.Executors$RunnableAdapter . call (Executors.java:511)
java.util.concurrent.FutureTask . run (FutureTask.java:266)
java.util.concurrent.ThreadPoolExecutor . runWorker (ThreadPoolExecutor.java:1149)
java.util.concurrent.ThreadPoolExecutor$Worker . run (ThreadPoolExecutor.java:624)
java.lang.Thread . run (Thread.java:748)
贴一个堆栈信息：
