这个问题与使用spring-dm导入osgi服务时发生的死锁有关(有时如下所述(。
我最近在SpringDM的ServiceDynamicInterceptor类中遇到了这个问题，它导致了死锁的情况。当从两个捆绑包加载两个应用程序上下文时，就会发生这种情况。假设应用ctx A导出一个osgi服务，应用ctx B导入从A导出的osgi服务。当两个捆绑包一起启动时，就会出现问题。当应用程序ctx A初始化时，spring会在发布osgi服务期间同步调用为该服务注册的侦听器。。假设应用ctx B同时被初始化并且osgi导入被执行。首先，它将osgi服务的侦听器添加到bundle上下文中，然后查找osgi服务。正如监听器被添加到bundle上下文中一样，应用程序ctx A会拾取它并执行监听器。此时，获取锁的应用程序ctx B试图查找尚未发布的osgi服务，因为正在调用等待释放相同锁的侦听器，从而导致死锁。在5分钟内(默认值(达到springbean创建超时后，应用ctx B将失败，ServiceUnavailableException导致BeanInitializationException。
我已经列出了在这两个线程中执行的代码。请注意，查找和侦听器都是在同一个文件ServiceDynamicInterceptor中定义的。
应用程序Ctx A正在等待锁定
145: synchronized (lock) {
146: servicePresent = (wrapper != null && wrapper.isServiceAlive());
147: }
应用程序Ctx B正在等待在发布osgi服务
428: private Object lookupService() {
429: synchronized (lock) {
430: return (Object) retryTemplate.execute(retryCallback);
431: }
432: }
正如我之前所说，当两个捆绑包一起重新启动时，有时会发生这种情况。然而，由于明显的原因，这种情况并非每次都发生。我的问题是，是否有任何方法可以避免这种死锁？
从线程转储中提取
应用程序Ctx A
"SpringOsgiExtenderThread-90" Id=908 in BLOCKED on lock=java.lang.Object@5a9a333f
owned by pool-45-thread-1 Id=798
at org.springframework.osgi.service.importer.support.internal.aop.ServiceDynamicInterceptor$Listener.serviceChanged(ServiceDynamicInterceptor.java:146)
at org.apache.felix.framework.util.EventDispatcher.invokeServiceListenerCallback(EventDispatcher.java:934)
at org.apache.felix.framework.util.EventDispatcher.fireEventImmediately(EventDispatcher.java:795)
at org.apache.felix.framework.util.EventDispatcher.fireServiceEvent(EventDispatcher.java:544)
at org.apache.felix.framework.Felix.fireServiceEvent(Felix.java:4596)
at org.apache.felix.framework.Felix.registerService(Felix.java:3604)
at org.apache.felix.framework.BundleContextImpl.registerService(BundleContextImpl.java:346)
at org.springframework.osgi.service.exporter.support.OsgiServiceFactoryBean.registerService(OsgiServiceFactoryBean.java:310)
at org.springframework.osgi.service.exporter.support.OsgiServiceFactoryBean.registerService(OsgiServiceFactoryBean.java:279)
at org.springframework.osgi.service.exporter.support.OsgiServiceFactoryBean$Executor.registerService(OsgiServiceFactoryBean.java:95)
at org.springframework.osgi.service.exporter.support.internal.controller.ExporterController.registerService(ExporterController.java:40)
at org.springframework.osgi.service.dependency.internal.DefaultMandatoryDependencyManager.startExporter(DefaultMandatoryDependencyManager.java:320)
at org.springframework.osgi.service.dependency.internal.DefaultMandatoryDependencyManager.checkIfExporterShouldStart(DefaultMandatoryDependencyManager.java:261)
at org.springframework.osgi.service.dependency.internal.DefaultMandatoryDependencyManager.discoverDependentImporterFor(DefaultMandatoryDependencyManager.java:254)
- locked org.springframework.osgi.service.exporter.support.OsgiServiceFactoryBean@2ae6baf0
at org.springframework.osgi.service.dependency.internal.DefaultMandatoryDependencyManager.addServiceExporter(DefaultMandatoryDependencyManager.java:187)
at org.springframework.osgi.service.dependency.internal.MandatoryDependencyBeanPostProcessor.postProcessAfterInitialization(MandatoryDependencyBeanPostProcessor.java:46)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsAfterInitialization(AbstractAutowireCapableBeanFactory.java:407)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1461)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225)
- locked java.util.concurrent.ConcurrentHashMap@25dfde15
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:589)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:925)
at org.springframework.osgi.context.support.AbstractDelegatedExecutionApplicationContext.access$1600(AbstractDelegatedExecutionApplicationContext.java:69)
at org.springframework.osgi.context.support.AbstractDelegatedExecutionApplicationContext$4.run(AbstractDelegatedExecutionApplicationContext.java:355)
- locked java.lang.Object@c6d4820
at org.springframework.osgi.util.internal.PrivilegedUtils.executeWithCustomTCCL(PrivilegedUtils.java:85)
at org.springframework.osgi.context.support.AbstractDelegatedExecutionApplicationContext.completeRefresh(AbstractDelegatedExecutionApplicationContext.java:320)
at org.springframework.osgi.extender.internal.dependencies.startup.DependencyWaiterApplicationContextExecutor$CompleteRefreshTask.run(DependencyWaiterApplicationContextExecutor.java:132)
at java.lang.Thread.run(Thread.java:745)
应用Ctx B
"pool-45-thread-1" Id=798 in TIMED_WAITING on lock=java.lang.Object@2b767b9b
at java.lang.Object.wait(Native Method)
at org.springframework.osgi.service.importer.support.internal.support.RetryTemplate.execute(RetryTemplate.java:106)
at org.springframework.osgi.service.importer.support.internal.aop.ServiceDynamicInterceptor.lookupService(ServiceDynamicInterceptor.java:430)
at org.springframework.osgi.service.importer.support.internal.aop.ServiceDynamicInterceptor.getTarget(ServiceDynamicInterceptor.java:415)
at org.springframework.osgi.service.importer.support.internal.aop.ServiceDynamicInterceptor.afterPropertiesSet(ServiceDynamicInterceptor.java:472)
at org.springframework.osgi.service.importer.support.OsgiServiceProxyFactoryBean.createProxy(OsgiServiceProxyFactoryBean.java:215)
at org.springframework.osgi.service.importer.support.AbstractServiceImporterProxyFactoryBean.getObject(AbstractServiceImporterProxyFactoryBean.java:86)
at org.springframework.osgi.service.importer.support.OsgiServiceProxyFactoryBean.getObject(OsgiServiceProxyFactoryBean.java:161)
at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean(FactoryBeanRegistrySupport.java:142)
at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.getObjectFromFactoryBean(FactoryBeanRegistrySupport.java:102)
- locked java.util.concurrent.ConcurrentHashMap@1a8ffb40
at org.springframework.beans.factory.support.AbstractBeanFactory.getObjectForBeanInstance(AbstractBeanFactory.java:1442)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:248)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1109)
at org.apache.camel.spring.spi.ApplicationContextRegistry.lookup(ApplicationContextRegistry.java:43)
at org.apache.camel.impl.CompositeRegistry.lookup(CompositeRegistry.java:51)
at org.apache.camel.impl.PropertyPlaceholderDelegateRegistry.lookup(PropertyPlaceholderDelegateRegistry.java:62)
at org.apache.camel.util.CamelContextHelper.lookup(CamelContextHelper.java:119)
at org.apache.camel.model.RouteBuilderDefinition.createRouteBuilder(RouteBuilderDefinition.java:64)
at org.apache.camel.core.xml.AbstractCamelContextFactoryBean.installRoutes(AbstractCamelContextFactoryBean.java:624)
at org.apache.camel.core.xml.AbstractCamelContextFactoryBean.afterPropertiesSet(AbstractCamelContextFactoryBean.java:276)
at org.apache.camel.spring.CamelContextFactoryBean.afterPropertiesSet(CamelContextFactoryBean.java:235)
at org.apache.camel.osgi.CamelContextFactoryBean.afterPropertiesSet(CamelContextFactoryBean.java:64)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1514)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1452)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225)
- locked java.util.concurrent.ConcurrentHashMap@1a8ffb40
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
at org.springframework.context.event.AbstractApplicationEventMulticaster.getApplicationListeners(AbstractApplicationEventMulticaster.java:155)
at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:86)
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:327)
at org.springframework.osgi.service.importer.support.internal.aop.ServiceDynamicInterceptor.publishEvent(ServiceDynamicInterceptor.java:439)
at org.springframework.osgi.service.importer.support.internal.aop.ServiceDynamicInterceptor.access$300(ServiceDynamicInterceptor.java:67)
at org.springframework.osgi.service.importer.support.internal.aop.ServiceDynamicInterceptor$EventSenderRetryTemplate.onMissingTarget(ServiceDynamicInterceptor.java:96)
at org.springframework.osgi.service.importer.support.internal.support.RetryTemplate.execute(RetryTemplate.java:95)
at org.springframework.osgi.service.importer.support.internal.aop.ServiceDynamicInterceptor.lookupService(ServiceDynamicInterceptor.java:430)
- locked java.lang.Object@5a9a333f
at org.springframework.osgi.service.importer.support.internal.aop.ServiceDynamicInterceptor.getTarget(ServiceDynamicInterceptor.java:415)
at org.springframework.osgi.service.importer.support.internal.aop.ServiceDynamicInterceptor.afterPropertiesSet(ServiceDynamicInterceptor.java:472)
at org.springframework.osgi.service.importer.support.OsgiServiceProxyFactoryBean.createProxy(OsgiServiceProxyFactoryBean.java:215)
at org.springframework.osgi.service.importer.support.AbstractServiceImporterProxyFactoryBean.getObject(AbstractServiceImporterProxyFactoryBean.java:86)
at org.springframework.osgi.service.importer.support.OsgiServiceProxyFactoryBean.getObject(OsgiServiceProxyFactoryBean.java:161)
at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean(FactoryBeanRegistrySupport.java:142)
at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.getObjectFromFactoryBean(FactoryBeanRegistrySupport.java:102)
- locked java.util.concurrent.ConcurrentHashMap@1a8ffb40
at org.springframework.beans.factory.support.AbstractBeanFactory.getObjectForBeanInstance(AbstractBeanFactory.java:1442)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:305)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:323)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:107)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1360)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1118)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:517)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225)
- locked java.util.concurrent.ConcurrentHashMap@1a8ffb40
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:607)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:925)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:472)
- locked java.lang.Object@62b8345f
at org.springframework.osgi.context.support.AbstractDelegatedExecutionApplicationContext.access$301(AbstractDelegatedExecutionApplicationContext.java:69)
at org.springframework.osgi.context.support.AbstractDelegatedExecutionApplicationContext$1.run(AbstractDelegatedExecutionApplicationContext.java:186)
at org.springframework.osgi.util.internal.PrivilegedUtils.executeWithCustomTCCL(PrivilegedUtils.java:85)
at org.springframework.osgi.context.support.AbstractDelegatedExecutionApplicationContext.normalRefresh(AbstractDelegatedExecutionApplicationContext.java:182)
at org.springframework.osgi.context.support.AbstractDelegatedExecutionApplicationContext$NoDependenciesWaitRefreshExecutor.refresh(AbstractDelegatedExecutionApplicationContext.java:89)
at org.springframework.osgi.context.support.AbstractDelegatedExecutionApplicationContext.refresh(AbstractDelegatedExecutionApplicationContext.java:175)
at com.xxx.bbb.core.extender.service.bbbManagedServiceFactory$1.run(BbbManagedServiceFactory.java:178)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
过去，我在Spring DM中遇到过类似的问题，我所做的解决方法是通过BundleActivator使用ServiceTracker跟踪服务。在某些情况下，我还必须自定义依赖该服务的所有代码(例如：自动布线(。太难看了。。。但它起了作用。经过一些这样的实验，我记得我还成功地使用了具有相同方法的FactoryBean。。。