Install Apache Tomcat 8 on Ubuntu 16.04

Install Java

Create Tomcat User

sudo groupadd tomcat
sudo useradd -s /bin/false -g tomcat -d /opt/tomcat tomcat

Install Tomcat

sudo mkdir /opt/tomcat
wget http://apache.mirrors.ionfish.org/tomcat/tomcat-8/v8.5.5/bin/apache-tomcat-8.5.5.tar.gz

Update Permissions

cd /opt/tomcat
sudo chgrp -R tomcat /opt/tomcat
sudo chmod -R g+r conf
sudo chmod g+x conf
sudo chown -R tomcat webapps/ work/ temp/ logs/

Create a systemd Service File

sudo update-java-alternatives -l
Output
java-1.8.0-openjdk-amd64       1081       /usr/lib/jvm/java-1.8.0-openjdk-amd64
sudo nano /etc/systemd/system/tomcat.service
[Unit]
Description=Apache Tomcat Web Application Container
After=network.target

[Service]
Type=forking

Environment=JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-amd64/jre
Environment=CATALINA_PID=/opt/tomcat/temp/tomcat.pid
Environment=CATALINA_HOME=/opt/tomcat
Environment=CATALINA_BASE=/opt/tomcat
Environment='CATALINA_OPTS=-Xms512M -Xmx1024M -server -XX:+UseParallelGC'
Environment='JAVA_OPTS=-Djava.awt.headless=true -Djava.security.egd=file:/dev/./urandom'

ExecStart=/opt/tomcat/bin/startup.sh
ExecStop=/opt/tomcat/bin/shutdown.sh

User=tomcat
Group=tomcat
UMask=0007
RestartSec=10
Restart=always

[Install]
WantedBy=multi-user.target
sudo systemctl daemon-reload
sudo systemctl start tomcat
sudo systemctl status tomcat

Configure Tomcat Web Management Interface

sudo nano /opt/tomcat/conf/tomcat-users.xml
<tomcat-users . . .>
    <user username="admin" password="password" roles="manager-gui,admin-gui"/>
</tomcat-users>

For the Manager app, type:

sudo nano /opt/tomcat/webapps/manager/META-INF/context.xml

For the Host Manager app, type:

sudo nano /opt/tomcat/webapps/host-manager/META-INF/context.xml
<Context antiResourceLocking="false" privileged="true" >
  <!--<Valve className="org.apache.catalina.valves.RemoteAddrValve"
         allow="127\.\d+\.\d+\.\d+|::1|0:0:0:0:0:0:0:1" />-->
</Context>
sudo systemctl restart tomcat

Access the Web Interface

http://server_domain_or_IP:8080

References
https://www.digitalocean.com/community/tutorials/how-to-install-apache-tomcat-8-on-ubuntu-16-04

Configure JSF with Gradle

build.gradle

group 'ir.iterator'
version '1.0-SNAPSHOT'

apply plugin: 'java'
apply plugin: 'war'

sourceCompatibility = 1.8

repositories {
    mavenCentral()
}

dependencies {
    testCompile group: 'junit', name: 'junit', version: '4.11'

    // https://mvnrepository.com/artifact/com.sun.faces/jsf-api
    compile group: 'com.sun.faces', name: 'jsf-api', version: '2.2.14'

    // https://mvnrepository.com/artifact/com.sun.faces/jsf-impl
    compile group: 'com.sun.faces', name: 'jsf-impl', version: '2.2.14'

    // https://mvnrepository.com/artifact/javax.servlet.jsp.jstl/javax.servlet.jsp.jstl-api
    compile group: 'javax.servlet.jsp.jstl', name: 'javax.servlet.jsp.jstl-api', version: '1.2.1'

    // https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api
    compile group: 'javax.servlet', name: 'javax.servlet-api', version: '3.1.0'
}

/src/main/webapp/WEB-INF/web.xml

<?xml version="1.0" encoding="UTF-8"?>  
 <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
            xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"  
            xsi:schemaLocation="http://java.sun.com/xml/ns/javaee  
      http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"  
            id="WebApp_ID" version="2.5">  
      <!-- Change to "Production" when you are ready to deploy -->  
      <context-param>  
           <param-name>javax.faces.PROJECT_STAGE</param-name>  
           <param-value>Development</param-value>  
      </context-param>  
      <servlet>  
           <servlet-name>Faces Servlet</servlet-name>  
           <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>  
           <load-on-startup>1</load-on-startup>  
      </servlet>  
      <!-- Map these files with JSF -->  
      <servlet-mapping>  
           <servlet-name>Faces Servlet</servlet-name>  
           <url-pattern>/faces/*</url-pattern>  
      </servlet-mapping>  
      <servlet-mapping>  
           <servlet-name>Faces Servlet</servlet-name>  
           <url-pattern>*.jsf</url-pattern>  
      </servlet-mapping>  
      <servlet-mapping>  
           <servlet-name>Faces Servlet</servlet-name>  
           <url-pattern>*.faces</url-pattern>  
      </servlet-mapping>  
      <servlet-mapping>  
           <servlet-name>Faces Servlet</servlet-name>  
           <url-pattern>*.xhtml</url-pattern>  
      </servlet-mapping>  
      <!-- Welcome page -->  
      <welcome-file-list>  
           <welcome-file>welcome.xhtml</welcome-file>  
      </welcome-file-list>  
 </web-app>  

References
http://b1102.blogspot.ru/2014/09/jsf-21-gralde-tomcat-hello-world.html