运行drool示例程序时出现异常

Question

我是drools的新手。我试图执行示例程序。我得到了这些异常

Exception in thread "main" java.lang.NoClassDefFoundError: org/drools/event /KnowledgeRuntimeEventManager
   at java.lang.Class.getDeclaredMethods0(Native Method)
   at java.lang.Class.privateGetDeclaredMethods(Unknown Source)
   at java.lang.Class.getMethod0(Unknown Source)
   at java.lang.Class.getMethod(Unknown Source)
   at sun.launcher.LauncherHelper.getMainMethod(Unknown Source)
   at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)
Caused by: java.lang.ClassNotFoundException: org.drools.event.KnowledgeRuntimeEventManager
   at java.net.URLClassLoader$1.run(Unknown Source)
   at java.net.URLClassLoader$1.run(Unknown Source)
   at java.security.AccessController.doPrivileged(Native Method)
   at java.net.URLClassLoader.findClass(Unknown Source)
   at java.lang.ClassLoader.loadClass(Unknown Source)
   at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
   at java.lang.ClassLoader.loadClass(Unknown Source)
    ... 6 more