tomcat project started error java web error: Choose unique values for the 'webAppRootKey' context-param in your

1, the error due to multiple tomcat --- webapp project, and webAppRootKey same name, delete an item or change the name of a project

<context-param>
<param-name>log4jConfigLocation</param-name>
<param-value>/WEB-INF/log4j.properties</param-value>
</context-param>
<context-param>
<param-name>webAppRootKey</param-name>
<param-value>webName.root</param-value>
</context-param>