I followed the instructions from this page.

Basically, I only did two things:

1. created a new JKS keystore from scratch with a self-signed certificate

keytool -genkey -alias tomcat -keyalg RSA 

2. uncommented the 8443 connector in the server.xml file in Tomcat's conf directory and modified it to read as follows:

   <Connector port="8443" protocol="org.apache.coyote.http11.Http11NioProtocol"
            maxThreads="150" SSLEnabled="true"
            scheme="https" secure="true"
            keystoreFile="${user.home}/.keystore" keystorePass="changeme"
            clientAuth="false" sslProtocol="TLS"/>

   … where the value for the keystorePass attribute had to match what I provided when I run the keytool program.

 5390  wget http://mirror.olnevhost.net/pub/apache/tomcat/tomcat-8/v8.5.8/bin/apache-tomcat-8.5.8.tar.gz
 5391  cd /opt/
 5393  sudo mv ~/Downloads/apache-tomcat-8.5.8.tar.gz .
 5394  sudo tar xvfz apache-tomcat-8.5.8.tar.gz
 5395  sudo ln -s apache-tomcat-8.5.8 tomcat8.5
 5396  cd tomcat8.5
 5401  sudo chown -R mperdikeas:mperdikeas  .