部署  公司后台管理系统中  关于jar包冲突的问题 ：

tomcat 启动的时候报错 如下： 

2014-3-10 0:56:48 org.apache.catalina.core.StandardContext listenerStart

严重: Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'approvaautojob' defined in ServletContext resource [/WEB-INF/fm-conf/spring-quartz.xml]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [org.springframework.scheduling.quartz.JobDetailBean]: Constructor threw exception; nested exception is java.lang.NoSuchMethodError: org.apache.commons.collections.SetUtils.orderedSet(Ljava/util/Set;)Ljava/util/Set;

Caused by: org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [org.springframework.scheduling.quartz.JobDetailBean]: Constructor threw exception; nested exception is java.lang.NoSuchMethodError: org.apache.commons.collections.SetUtils.orderedSet(Ljava/util/Set;)Ljava/util/Set;

Caused by: java.lang.NoSuchMethodError: org.apache.commons.collections.SetUtils.orderedSet(Ljava/util/Set;)Ljava/util/Set;

 at org.quartz.JobDetail.<init>(JobDetail.java:85)

 at org.springframework.scheduling.quartz.JobDetailBean.<init>(JobDetailBean.java:45)

 at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

 at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)

 at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)

 at java.lang.reflect.Constructor.newInstance(Constructor.java:513)

 at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:85)

 at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:61)

 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:752)

 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:717)

 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:386)

 at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:249)

 at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:155)

 at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:246)

 at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:160)

 at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:291) 

 at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:352)

 at org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:245)

 at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:188)

 at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:49)

 at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4206)

 at org.apache.catalina.core.StandardContext.start(StandardContext.java:4705)

 at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:799)

 at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:779)

 at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:601)

 at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1079)

 at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:1002)

 at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:506)

 at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1317)

 at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:324)

 at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:142)

 at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1065)

 at org.apache.catalina.core.StandardHost.start(StandardHost.java:840)

 at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1057)

 at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:463)

 at org.apache.catalina.core.StandardService.start(StandardService.java:525)

 at org.apache.catalina.core.StandardServer.start(StandardServer.java:754)

 at org.apache.catalina.startup.Catalina.start(Catalina.java:595)

 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

 at java.lang.reflect.Method.invoke(Method.java:597)

 at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:289)

 at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)

2014-3-10 0:56:48 org.apache.catalina.core.StandardContext start

知道是Spring初始化创建bean的时候失败了，原因是jar包冲突，但一直不知道是哪个jar包冲突，后来google了几下，在这篇文章中找到了答案（我的英文杠杠的）

：

终于知道是commons-collections-2.1.1  和 commons-collections-3.2.jar  冲突了，尝试了两次，第一次删了高版本的，不行，第二次把低版本删了。重启就可以了。 （其实还是没有注意看报错的原因，报错那里明明提示了collections  JAR包冲突了，见本人在报错信息中标注的红色字体，Caused by: 的后面提示那里）

疑问：  有相同版本的时候，不是都先加载高版本的吗？ 纳闷了。