Tomcat 9 context docBase redirect to https

I have trouble with Tomcat 9 configuration on Ubuntu. I have deployed 1 application under Tomcat. Created SSL and redirect HTTP to HTTPS. My appliaction name for example - example :) So I have this:

Part of my server.xml config file:

<Connector port="80" protocol="HTTP/1.1"
           connectionTimeout="60000"
           redirectPort="443"
           enableLookups="false"
           useBodyEncodingForURI="true"/>

<Connector port="443" protocol="HTTP/1.1"
           maxThreads="150"
           SSLEnabled="true"
           scheme="https"
           secure="true"
           clientAuth="false"
           sslProtocol="TLS"
           keystoreFile="path to cert"
           keystoreType="PKCS12"
           keystorePass="cert password"/>

and in EOF of web.xml i have:

<security-constraint>
<web-resource-collection>
  <web-resource-name>Protected Context</web-resource-name>
  <url-pattern>/*</url-pattern>
</web-resource-collection>
<user-data-constraint>
  <transport-guarantee>CONFIDENTIAL</transport-guarantee>
</user-data-constraint>
</security-constraint>

Redirect works fine, when I type http://localhost I automatically will be redirected to HTTPS, but only if I type http://localhost. When I type http://localhost/example - redirect doesn't work, why?

So, I add to index.jsp in webapps/ROOT:

<%
String redirectURL = "/example";
response.sendRedirect(redirectURL);
%>

redirect work fine

So, I would like to permanent redirect "example" to root, so I added to my server.xml content:

<Context path="" docBase="example" debug="0" reloadable="true"></Context>

Redirect work fine, when I type http://localhost I see content of example. But there is problem - HTTP - HTTPS redirect doesn't work after add "context". Why? I spent half a day with Tomcat configuration and I don't know why redirect doesn't work after adding context.