When you call a page that does not exist in the tomcat server, or when an existing page returns an error, the tomcat server will display the version number. This might be a security risk, especially if you are running an old Tomcat server that has some known exploits.
How to hide the version number from the error pages
1.Go to $CATALINA_HOME/lib, and create the org/apache/catalina/util directory
2.Under org/apache/catalina/util directory create ServerInfo.properties file
3.Now add below lines
server.info=XXX (What ever yo want)
4.Now restart tomcat server and on error page it will show the value you have specified in ServerInfo.properties file .