You don't have to use Tomcat installation as a server location. It is much easier just to copy the files in the ROOT folder.
Eclipse forgets to copy the default apps (ROOT, examples, etc.) when
it creates a Tomcat folder inside the Eclipse workspace. Go to
C:\apache-tomcat-7.0.8\webapps
, R-click on the ROOT folder and copy
it. Then go to your Eclipse workspace, go to the .metadata
folder, and
search for "wtpwebapps". You should find something like
your-eclipse-workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps
(or ../tmp1/wtpwebapps
if you already had another server registered
in Eclipse). Go to the wtpwebapps
folder, R-click, and paste ROOT (say
"yes" if asked if you want to merge/replace folders/files). Then
reload http://localhost/
to see the Tomcat welcome page.
Source: HTTP Status 404 error in tomcat