title: java.lang.NoClassDefFoundError: javax/servlet/Filter
body: <p>I am getting this error when i start tomcat </p>
  
  <pre><code>java.lang.NoClassDefFoundError: javax/servlet/Filter
  at java.lang.ClassLoader.findBootstrapClass(Native Method)
  at java.lang.ClassLoader.findBootstrapClass0(Unknown Source)
  at java.lang.ClassLoader.loadClass(Unknown Source)
  at java.lang.ClassLoader.loadClass(Unknown Source)
  at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
  at java.lang.ClassLoader.loadClass(Unknown Source)
  at      org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1301)
  at    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1232)
  at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:207)
  at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:302)
  at org.apache.catalina.core.ApplicationFilterConfig.&lt;init&gt;(ApplicationFilterConfig.java:78)
  at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:3666)
  at org.apache.catalina.core.StandardContext.start(StandardContext.java:4258)
  at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1014)
  at org.apache.catalina.core.StandardHost.start(StandardHost.java:736)
  at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1014)
  at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443)
  at org.apache.catalina.core.StandardService.start(StandardService.java:448)
  at org.apache.catalina.core.StandardServer.start(StandardServer.java:700)
  at org.apache.catalina.startup.Catalina.start(Catalina.java:552)
  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
  at java.lang.reflect.Method.invoke(Unknown Source)
  at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:295)
  at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:433)
  </code></pre>
  
  <p>i have already put the servlet.jar in classpath and tomcat_home/commons/lib folder</p>
  
  <p>please can any one suggest what to do.</p>