Servlet is not created for some reason in Vaadin 7

Question

I wanted to test the basics of Vaadin, but I can't load my main page, I keep getting 404 Status message. I am deploying the WAR file to my Glassfish server. The sample project from vaadin.com tutorial is working, so the server is not the problem. Any suggestion is much appreciated.

** UPDATE ** The problem is that the servlet is not generated. See the code below in the MyUI: MyUIServlet is configured but at the end, it is missing from the WAR file.

This is the Main UI:

import com.vaadin.annotations.Theme;
import com.vaadin.annotations.VaadinServletConfiguration;
import com.vaadin.cdi.CDIUI;
import com.vaadin.cdi.CDIViewProvider;
import com.vaadin.cdi.server.VaadinCDIServlet;
import com.vaadin.navigator.Navigator;
import com.vaadin.server.VaadinRequest;
import com.vaadin.ui.UI;

import javax.inject.Inject;
import javax.servlet.annotation.WebServlet;

@CDIUI("")
@Theme("mytheme")
public class MyUI extends UI {

    @Inject
    private CDIViewProvider viewProvider;

    @Override
    protected void init(VaadinRequest request) {
        getPage().setTitle("Training Application");
        final Navigator navigator = new Navigator(this, this);
        navigator.addProvider(viewProvider);
        navigator.navigateTo(MainView.VIEW_NAME);
    }

    @WebServlet(urlPatterns = "/*", name = "MyUIServlet", asyncSupported = true)
    @VaadinServletConfiguration(ui = MyUI.class, productionMode = true)
    public static class MyUIServlet extends VaadinCDIServlet {
    }
}

And this is the View where I want to navigate, but for some reason, it does not work:

import com.vaadin.cdi.CDIView;
import com.vaadin.navigator.View;
import com.vaadin.navigator.ViewChangeListener;
import com.vaadin.navigator.ViewChangeListener.ViewChangeEvent;
import com.vaadin.ui.Label;
import com.vaadin.ui.VerticalLayout;

@CDIView(MainView.VIEW_NAME)
public class MainView extends VerticalLayout implements View {
    
    public static final String VIEW_NAME = "";

    @Override
    public void enter(ViewChangeListener.ViewChangeEvent viewChangeEvent) {
        Label titleLabel = new Label("Ships");
        addComponents(titleLabel);
        setSpacing(true);
        setMargin(true);
    }
    
}

POM.xml:

<project xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>***</groupId>
        <artifactId>***</artifactId>
        <version>***</version>
    </parent>
    <artifactId>frontend</artifactId>
    <packaging>war</packaging>

    <properties>
        <vaadin.version>7.6.8</vaadin.version>
    </properties>
    <repositories>
        <repository>
            <id>vaadin-addons</id>
            <url>http://maven.vaadin.com/vaadin-addons</url>
        </repository>
    </repositories>

    <dependencies>
        <dependency>
            <groupId>***</groupId>
            <artifactId>core</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.0.1</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>com.vaadin</groupId>
            <artifactId>vaadin-server</artifactId>
            <version>${vaadin.version}</version>
        </dependency>
        <dependency>
            <groupId>com.vaadin</groupId>
            <artifactId>vaadin-push</artifactId>
            <version>${vaadin.version}</version>
        </dependency>
        <dependency>
            <groupId>com.vaadin</groupId>
            <artifactId>vaadin-client</artifactId>
            <version>${vaadin.version}</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>com.vaadin</groupId>
            <artifactId>vaadin-client-compiled</artifactId>
            <version>${vaadin.version}</version>
        </dependency>
        <dependency>
            <groupId>com.vaadin</groupId>
            <artifactId>vaadin-themes</artifactId>
            <version>${vaadin.version}</version>
        </dependency>
        <dependency>
            <groupId>com.vaadin</groupId>
            <artifactId>vaadin-cdi</artifactId>
            <version>1.0.1</version>
        </dependency>
    </dependencies>
    
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>com.vaadin</groupId>
                <artifactId>vaadin-maven-plugin</artifactId>
                <version>${vaadin.version}</version>
                <configuration>
                    <extraJvmArgs>-Xmx512M -Xss1024k</extraJvmArgs>
                    <webappDirectory>${basedir}/target/classes/VAADIN/widgetsets</webappDirectory>
                    <draftCompile>false</draftCompile>
                    <compileReport>false</compileReport>
                    <style>OBF</style>
                    <strict>true</strict>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>update-theme</goal>
                            <goal>update-widgetset</goal>
                            <goal>compile</goal>
                            <!-- Comment out compile-theme goal to use on-the-fly theme compilation -->
                            <goal>compile-theme</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
            
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-clean-plugin</artifactId>
                <version>2.6.1</version>
                <!-- Clean up also any pre-compiled themes -->
                <configuration>
                    <filesets>
                        <fileset>
                            <directory>src/main/webapp/VAADIN/themes</directory>
                            <includes>
                                <include>**/styles.css</include>
                                <include>**/styles.scss.cache</include>
                            </includes>
                        </fileset>
                    </filesets>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

Answer 1

Solved: I had to make a web.xml (https://vaadin.com/docs/v7/framework/articles/CreatingABasicApplication.html) for the servlet configuration, and delete the javax.servlet declaration:

@WebServlet(urlPatterns = "/*", name = "MyUIServlet", asyncSupported = true)
@VaadinServletConfiguration(ui = MyUI.class, productionMode = false)
public static class MyUIServlet extends VaadinServlet {
}