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