Tomcat7.0 start Could not find the main class: org.apache.catalina.startup.Bootstrap.

java.lang.NoClassDefFoundError: org/apache/juli/logging/LogFactory
at org.apache.catalina.startup.Bootstrap.<clinit>(Bootstrap.java:60)
Caused by: java.lang.ClassNotFoundException: org.apache.juli.logging.LogFactory
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
... 1 more

Exception in thread "main" 

1. In Eclipse, Open the "Server" tab.
2. Double click on the "Tomcat6" entry to see the configuration.
3. Then click on the "Open launch configuration" link in the "General information" block.
4. In the dialog, select the "Classpath" tab.
5. Click the "Add external jar" button.
6. Select the file "/usr/share/tomcat6/bin/tomcat-juli.jar"
7. Close the dialog.
8. Start tomcat 7 from Eclipse.