Minimal Standalone Vaadin Application Jar with Maven (~ 7.7MB)

App.java

package org.vaadin.lightvaadin;

import com.vaadin.server.VaadinServlet;
import java.util.EventListener;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.servlet.ServletContextHandler;
import org.eclipse.jetty.servlet.ServletHolder;

/** Minimal Servlet bootstrap for Vaadin application.
 *
 * @author Sami Ekblad
 */
public class App {

    public static void main(String[] args) {
        Server server = new Server(8080);

        ServletContextHandler contextHandler
                = new ServletContextHandler(ServletContextHandler.SESSIONS);
        contextHandler.setContextPath("/");

        ServletHolder sh = new ServletHolder(new VaadinServlet());
        contextHandler.addServlet(sh, "/*");
        contextHandler.setInitParameter("ui", HelloWorldUI.class.getCanonicalName());

        // Register cdn.virit.in if present
        try {
            Class cls = Class.forName("in.virit.WidgetSet");
            if (cls != null) {
                contextHandler.getSessionHandler().addEventListener((EventListener) cls.newInstance());
            }
        } catch (Exception ex) {
            Logger.getLogger(App.class.getName()).log(Level.SEVERE, null, ex);
        }

        server.setHandler(contextHandler);

        try {
            server.start();
            server.join();

        } catch (Exception ex) {
            Logger.getLogger(App.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
}

HelloWorldUI.java

package org.vaadin.lightvaadin;

import com.vaadin.annotations.Theme;
import com.vaadin.annotations.Title;
import com.vaadin.server.VaadinRequest;
import com.vaadin.ui.*;
import com.vaadin.ui.Button.ClickEvent;
import java.util.Date;

@Title("Light Vaadin")
@Theme("valo")
public class HelloWorldUI extends UI {

    private static final long serialVersionUID = 1L;
    private CssLayout layout;

    protected void init(VaadinRequest request) {
        layout = new CssLayout();
        setContent(layout);
        layout.addComponent(new Label("Hello world"));
        layout.addComponent(new Button("Click me", new Button.ClickListener() {

            @Override
            public void buttonClick(ClickEvent event) {
                Notification.show("Hello at " + new Date());
            }
        }));
    }
}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>org.vaadin.directory</groupId>
    <artifactId>light-vaadin</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.7</maven.compiler.source>
        <maven.compiler.target>1.7</maven.compiler.target>
        <vaadin.version>7.4.2</vaadin.version>
        <jetty.version>9.2.3.v20140905</jetty.version>
    </properties>
    
    <dependencies>
        <dependency>
            <groupId>com.vaadin</groupId>
            <artifactId>vaadin-server</artifactId>
            <version>${vaadin.version}</version>
            <type>jar</type>
            <exclusions>
                <exclusion>
                    <groupId>com.vaadin.external.flute</groupId>
                    <artifactId>flute</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>com.vaadin.external.google</groupId>
                    <artifactId>guava</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>com.vaadin</groupId>
                    <artifactId>vaadin-sass-compiler</artifactId>
                </exclusion>
            </exclusions>        
        </dependency>
        
        <!-- Instead of Valo, we use dawn -->
        <dependency>
            <groupId>org.peimari</groupId>
            <artifactId>dawn</artifactId>
            <version>4</version>
        </dependency>        
        <dependency>
            <groupId>org.eclipse.jetty</groupId>
            <artifactId>jetty-webapp</artifactId>
            <version>${jetty.version}</version>
            <type>jar</type>
        </dependency>
        
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>in.virit.vwscdn</groupId>
                <artifactId>vwscdn-maven-plugin</artifactId>
                <version>1.3.3</version>
                <executions>
                    <execution>
                        <phase>generate-sources</phase>
                        <goals>
                            <goal>generate</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <artifactId>maven-assembly-plugin</artifactId>
                <configuration>
                    <archive>
                        <manifest>
                            <mainClass>org.vaadin.lightvaadin.App</mainClass>
                        </manifest>
                    </archive>
                    <descriptorRefs>
                        <descriptorRef>jar-with-dependencies</descriptorRef>
                    </descriptorRefs>
                </configuration>
                <executions>
                    <execution>
                        <id>make-assembly</id> 
                        <phase>package</phase>
                        <goals>
                            <goal>single</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>   
        </plugins>
    </build>
    
    <repositories>
        <repository>
            <id>vaadin-addons</id>
            <url>http://maven.vaadin.com/vaadin-addons</url>
        </repository>
    </repositories>
</project>

Thanks for sharing this code. I have some questions.

• Does it run using a simple java -jar XXXXX?
• How can I add it as developed vaadin app?

This code works, but widgetset is not compiled and and there are no stiles.

Hello, I got this error:
Nov 08, 2016 8:33:34 PM dwbdip.web.jetty.App main
SEVERE: null
java.lang.ClassNotFoundException: in.virit.WidgetSet
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:264)
at dwbdip.web.jetty.App.main(App.java:29)

who can tell me which jar file i need to add?

@sunke-github, you can ignore the error, it's essentially looking for a plugin and if it finds it, it will initialize it. The error is simply there to tell you that it didn't find the plugin

Here is an upgraded version and a bit smaller size: https://github.com/amahdy/vaadin-light
I've also included some instructions on how to get it to work, and removed broken dependencies.