What should a Spring Boot main file look to host a site on Heroku?

[Franklin Oliveira]

I have a project on IntelliJ and GitHub repositories with Wicket and Spring Boot frameworks. I have already created a Start.main Java file, like so:

package website.fgto.royals_of_britain;
 
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.webapp.WebAppContext;
 
public class Start {  
    public static void main(String[] args) throws Exception {
 
        String webPort = System.getenv("PORT");
 
        if (webPort == null || webPort.isEmpty()) {
            webPort = "8080";
    }
 
        String webappDirLocation = "src/main/webapp/";
 
        Server server = new Server(Integer.valueOf(webPort));
        WebAppContext root = new WebAppContext();
        root.setContextPath("/");
        root.setDescriptor(webappDirLocation + "/WEB-INF/web.xml");
        root.setResourceBase(webappDirLocation);
        root.setParentLoaderPriority(true);
 
        server.setHandler(root);
        server.start();
        server.join();
    }
}

I have been advised that while a Start.main Java file isn’t useful, perhaps a Spring Boot main file may be what my project needs to get onto Heroku. How would the main file be developed differently if it were to be made a Spring Boot main file?

P.S. The sources that inspired me when I developed the Java main file were, as so:

http://wicketinaction.com/2011/09/git-wicket-running-on-heroku/
https://github.com/dashorst/heroku-wicket-examples/commit/9a4b2b9273467c03b868ffa4537c4dc6e7475b30
https://devcenter.heroku.com/articles/java-webapp-runner
https://devcenter.heroku.com/articles/deploying-spring-boot-apps-to-heroku
https://devcenter.heroku.com/articles/github-integration
https://github.com/alexo/heroku-wicket-web-app