- Create a own profile - this allows more flexibility
 
<profile>
    <id>jetty-run</id>
</profile>
<plugin>
    <groupId>org.mortbay.jetty</groupId>
    <artifactId>jetty-maven-plugin</artifactId>
    <configuration>
        <webAppSourceDirectory>${basedir}/src/main/webapp</webAppSourceDirectory>
        <scanIntervalSeconds>2</scanIntervalSeconds>
        <scanTargets>
            <scanTarget>src/main/java</scanTarget>
        </scanTargets>
    </configuration>
    <executions>
        <execution>
            <phase>package</phase>
            <goals>
                <goal>run</goal>
            </goals>
        </execution>
    </executions>
</plugin>
<properties>
    <maven.test.skip>true</maven.test.skip>
</properties>
<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-war-plugin</artifactId>
    <executions>
        <execution>
            <id>default-war</id>
            <phase>none</phase>
        </execution>
    </executions>
</plugin>
- Skip optimzation (we use the primefaces-extensions plugin for this)
 
<plugin>
    <groupId>org.primefaces.extensions</groupId>
    <artifactId>resources-optimizer-maven-plugin</artifactId>
    <executions>
        <execution>
            <id>optimize</id>
            <phase>none</phase>
        </execution>
    </executions>
</plugin>
@Override
protected void doGet(final HttpServletRequest request, final HttpServletResponse response)
    throws ServletException, IOException
{
    final OutputStream ouputStream = response.getOutputStream();
    response.setContentType(getServletConfig().getInitParameter("contentType");
    final List<File> filesToMerge = getFiles(getServletContext().getRealPath(getServletConfig().getInitParameter("includeDirectory")));
    for (final File fileToMerge : filesToMerge) {
    final FileInputStream inputStream = new FileInputStream(fileToMerge);
        IOUtils.copy(inputStream, ouputStream);
        inputStream.close();
    }
    ouputStream.close();
}
We just create a second web.xml (this is just for localhost and jetty) with the name "web-localhost.xml" in your "src/main/webapp/WEB-INF" directory with the following servlet mapping
<servlet>
    <servlet-name>Merge Javascript Servlet</servlet-name>
    <servlet-class>xxx.servlet.MergeResourceServlet</servlet-class>
    <init-param>
        <param-name>includeDirectory</param-name>
        <param-value>/javascript/</param-value>
    </init-param>
    <init-param>
        <param-name>contentType</param-name>
        <param-value>application/x-javascript</param-value>
    </init-param>
</servlet>
<servlet-mapping>
    <servlet-name>Merge Javascript Servlet</servlet-name>
    <url-pattern>/javascript/bundle.js</url-pattern>
</servlet-mapping>
<plugin>
    <groupId>org.mortbay.jetty</groupId>
    <artifactId>jetty-maven-plugin</artifactId>
    <configuration>
        <webAppConfig>
            <overrideDescriptor>src/main/webapp/WEB-INF/web-localhost.xml</overrideDescriptor>
        </webAppConfig>
        ...
    </configuration>
</plugin>
Finished! You will be able to start jetty now via "mvn package -P jetty-run".