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今天分享一个简单的hang的maven测试例子，download了系统代码之后发现系统load过程中，mvn 的unit test跑着跑着hang住了，试了2次都是一样，有段时间没完系统了，一下不太想得明白原因，就dump thread分析了下，记录下实践过程：
1. 系统是unix的，直接使用 ps -aux命令找到挂掉的java进程
ps -aux
root 2958 6.4 4.9 2107828 87636 pts/1 Sl+ 09:23 0:10 java -agentpath2. 用jstack命令dump java进程中的thread，很容易就发现了main thread在等待socketRead0数据，这个等待是ehcache的PeerListener引起的，因为mvn的unit test没有启动2个应用做测试，当然是等待通不过了，把unit test的配置脚本修改成单节点测试后，问题得到解决。
[root@cloudlu CustomerSecurityManagementDAO]# jstack 2958
2014-10-14 09:26:12Full thread dump OpenJDK 64-Bit Server VM (24.65-b04 mixed mode):"main" prio=10 tid=0x00007f963c019800 nid=0xb91 runnable [0x00007f9642658000] java.lang.Thread.State: RUNNABLE at java.net.SocketInputStream.socketRead0(Native Method) at java.net.SocketInputStream.read(SocketInputStream.java:152) at java.net.SocketInputStream.read(SocketInputStream.java:122) at java.io.BufferedInputStream.fill(BufferedInputStream.java:235) at java.io.BufferedInputStream.read(BufferedInputStream.java:254) - locked <0x00000000cc0077a8> (a java.io.BufferedInputStream) at java.io.DataInputStream.readByte(DataInputStream.java:265) at sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:214) at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:378) at sun.rmi.registry.RegistryImpl_Stub.rebind(Unknown Source) at java.rmi.Naming.rebind(Naming.java:177) at net.sf.ehcache.distribution.RMICacheManagerPeerListener.bind(RMICacheManagerPeerListener.java:234) at net.sf.ehcache.distribution.RMICacheManagerPeerListener.notifyCacheAdded(RMICacheManagerPeerListener.java:536) at net.sf.ehcache.event.CacheManagerEventListenerRegistry.notifyCacheAdded(CacheManagerEventListenerRegistry.java:159) at net.sf.ehcache.CacheManager.addCacheNoCheck(CacheManager.java:1346) at net.sf.ehcache.CacheManager.addConfiguredCaches(CacheManager.java:758) at net.sf.ehcache.CacheManager.doInit(CacheManager.java:459) at net.sf.ehcache.CacheManager.init(CacheManager.java:377) - locked <0x00000000da5566c0> (a net.sf.ehcache.CacheManager) at net.sf.ehcache.CacheManager.(CacheManager.java:259) at net.sf.ehcache.CacheManager.newInstance(CacheManager.java:1037) - locked <0x00000000da556878> (a java.lang.Class for net.sf.ehcache.CacheManager) at net.sf.ehcache.CacheManager.newInstance(CacheManager.java:818) at net.sf.ehcache.CacheManager.create(CacheManager.java:799) - locked <0x00000000da556878> (a java.lang.Class for net.sf.ehcache.CacheManager) at org.hibernate.cache.ehcache.SingletonEhCacheRegionFactory.start(SingletonEhCacheRegionFactory.java:73) at org.hibernate.internal.CacheImpl. (CacheImpl.java:70) at org.hibernate.engine.spi.CacheInitiator.initiateService(CacheInitiator.java:40) at org.hibernate.engine.spi.CacheInitiator.initiateService(CacheInitiator.java:35) at org.hibernate.service.internal.SessionFactoryServiceRegistryImpl.initiateService(SessionFactoryServiceRegistryImpl.java:91) at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:177) at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:151) at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:132) at org.hibernate.internal.SessionFactoryImpl. (SessionFactoryImpl.java:264) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1794) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1865) at org.springframework.orm.hibernate4.LocalSessionFactoryBuilder.buildSessionFactory(LocalSessionFactoryBuilder.java:343) at org.springframework.orm.hibernate4.LocalSessionFactoryBean.buildSessionFactory(LocalSessionFactoryBean.java:431) at org.springframework.orm.hibernate4.LocalSessionFactoryBean.afterPropertiesSet(LocalSessionFactoryBean.java:416) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1612) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1549) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:539) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) - locked <0x00000000d9f68c78> (a java.util.concurrent.ConcurrentHashMap) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195) at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:328) at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:108) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1456) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1197) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) - locked <0x00000000d9f68c78> (a java.util.concurrent.ConcurrentHashMap) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195) at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:328) at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:108) at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveManagedMap(BeanDefinitionValueResolver.java:384) at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:165) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1456) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1197) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) - locked <0x00000000d9f68c78> (a java.util.concurrent.ConcurrentHashMap) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195) at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:703) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:760) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482) - locked <0x00000000d9f621b0> (a java.lang.Object) at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:125) at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:60) at org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.delegateLoading(AbstractDelegatingSmartContextLoader.java:100) at org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.loadContext(AbstractDelegatingSmartContextLoader.java:250) at org.springframework.test.context.CacheAwareContextLoaderDelegate.loadContextInternal(CacheAwareContextLoaderDelegate.java:64) at org.springframework.test.context.CacheAwareContextLoaderDelegate.loadContext(CacheAwareContextLoaderDelegate.java:91) - locked <0x00000000d9f25308> (a org.springframework.test.context.ContextCache) at org.springframework.test.context.DefaultTestContext.getApplicationContext(DefaultTestContext.java:101) at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:109) at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:75) at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:331) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:213) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:290) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:292) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:233) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:87) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229) at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71) at org.junit.runners.ParentRunner.run(ParentRunner.java:309) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:176) at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:264) at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:153) at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:124) at org.apache.maven.surefire.booter.ForkedBooter.invokeProviderInSameClassLoader(ForkedBooter.java:200) at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:153) at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:103)"VM Thread" prio=10 tid=0x00007f963c0a2800 nid=0xb92 runnable "VM Periodic Task Thread" prio=10 tid=0x00007f963c341800 nid=0xb99 waiting on conditionJNI global references: 327
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