.war files are just .zip files, WEB

you don't need to recompile to change some settings, just
unzip track.war and zip -r /bla/track.war . (in the root of the unpacked stuff)
make sure you have no caching issues while testing your changed
paramters.

you can check in the deploy directory: /var/lib/tomcat9/webapps/track
and in the developer tools of the browser

track.war has a config file WEB-INF/private.xml, it sets the
'key' of openlayers.js (which openlayers to use) It uses
openlayers 2 (nothing like the new openlayers 3 - 6 -?).

maps/OpenLayers.js is eniterly differen from openlayers/OpenLayers.js
the latter calls the former. Everthing should be https, so that
the webbrowser does not complain about mixed content

tomcat9 logs in /var/log/tomcat9/catalina.out

use tomcat 9.0.16-5 or later (9.0.16-4 doesnt have a sysvinit startup scipt)

server startup can take a LONG time, do not despair!

to enable ssl in tomcat (not needed, because we proxy) use
APR/native implementation

    <!-- Define a SSL/TLS HTTP/1.1 Connector on port 8443 with HTTP/2
         This connector uses the APR/native implementation which always uses
         OpenSSL for TLS.
         Either JSSE or OpenSSL style configuration may be used. OpenSSL style
         configuration is used below.
    -->
    <!--
    <Connector port="8443" protocol="org.apache.coyote.http11.Http11AprProtocol"
               maxThreads="150" SSLEnabled="true" >
        <UpgradeProtocol className="org.apache.coyote.http2.Http2Protocol" />
        <SSLHostConfig>
                <Certificate certificateKeyFile="/etc/letsencrypt/live/penta.snel.it/privkey.pem"
                         certificateFile="/etc/letsencrypt/live/penta.snel.it/cert.pem"
                        certificateChainFile="/etc/letsencrypt/live/penta.snel.it/chain.pem"/>
        </SSLHostConfig>
    </Connector>
    -->

track.war points to https:// tile server of openstreetmap
gprmc.war is a server to receive updates from GPS devices

in tomcat9 the app is exposed on localhost:8080/track/Track
and localhost:8080/gprmc/Data

apache2 can proxy to it using

<Location "/track">
	ProxyPass http://localhost:8080/track
        ProxyPassReverse http://localhost:8080/track
        AuthType Basic
      	AuthName "Track"
        AuthBasicProvider external
        AuthExternal pwauth
        Require user rsnel mandy
</Location>