Spark app serves method

Main.java

public class Main {

    public static void main(String[] args) {
        initApi();
    }
    
    public static void initApi() {
        port(8080);
        get("/", MainResource::handleMain);
    }
}
public class MainResource { //In other file
    public static Object handleMain(Request request, Response response) {
        String htmlCode = "<div>Hello, someone :)</div>";
        if (request.attribute("username") != null) {
            htmlCode = "<div>Hello, " + request.attribute("username") + ":)</div>";
        }
        return htmlCode;
    }