升级到 Velocity 2.0 后的启动异常 java.lang.ClassN?400报错

试着将自己的项目中的 velocity 以及 velocity-tools 都升级到 2.0 版本后，启动应用报错：

java.lang.ClassNotFoundException: org.apache.velocity.runtime.log.Log

发现在 engine 包和 tools 包中都没有这个类，这个类在哪个包里呢？

完整异常信息：

 java.lang.ClassNotFoundException: org.apache.velocity.runtime.log.Log
        at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1333)
        at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1180)
        at java.lang.Class.getDeclaredMethods0(Native Method)
        at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)
        at java.lang.Class.getDeclaredMethods(Class.java:1975)
        at org.apache.catalina.util.Introspection.getDeclaredMethods(Introspection.java:127)
        at org.apache.catalina.core.DefaultInstanceManager.populateAnnotationsCache(DefaultInstanceManager.java:357)
        at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:173)
        at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:151)
        at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1105)
        at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1041)
        at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4922)
        at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5204)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
        at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1396)
        at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1386)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)