Not able to run a Vaadin application on remote server

Question

I am building a Vaadin application with Java. Here is the folder structure.

- com
-- my
--- WebTool
---- ToolUI.java
---- View_1.java
---- View_2.java

The entry point to the application is ToolUI.java and has the method init() that takes VaadinRequest as a parameter. It is this file where I add the views Views_1 and View_2 as views of the application and add navigations among them. Everything runs great when I run the application via the Eclipse IDE.

Now I have a requirement that I have to deploy this application on a remote server. So I created a war of the project and deployed on the server by the name MyWebTool.war.

Now when I try running the war with the command

java -jar MyWebTool.war

it gives me the error: Can't execute war no main manifest attribute, in MyWebTool.war

I am not sure what to add the main class as since the init method gets invoked and sets the app running. So I put a blank main function inside the MyWebToolUI.java and added this dependency in the pom.xml file.

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-war-plugin</artifactId>
    <version>2.6</version>
    <configuration>
        <archive>
            <manifest>
                <addClasspath>true</addClasspath>
                <mainClass>com.my.WebTool.ToolUI</mainClass>
            </manifest>
        </archive>
      <failOnMissingWebXml>false</failOnMissingWebXml>
      <!-- Exclude an unnecessary file generated by the GWT compiler. -->
      <packagingExcludes>WEB-INF/classes/VAADIN/widgetsets/WEB-INF/**</packagingExcludes>
    </configuration>
</plugin>

But now when trying to run the application it says Could not find or load main class com.my.WebTool.ToolUI

Can please somebody shed light on this? I don't know if I am missing something simple here but at this point, I am stuck. Thanks a lot.

Answer 1

For running war packaged applications, you will need a servlet container. The servlet container provides all the basic infrastructure needed to run java based web applications.

One of the most common ways to do this, is to deploy the war file to a tomcat installation.