To remedy this use the following steps:

1. Make the webapp directory the same as the output for your gwt code.

   ...
   <plugin>
   	<groupId>org.apache.maven.plugins</groupId>
   	<artifactId>maven-war-plugin</artifactId>
   	<configuration>
   		<webappDirectory>${project.build.directory}/${project.build.finalName}/my.long.package.name.Application	</webappDirectory>
   	</configuration>
   </plugin>
   ...

2. Ensure that your rpc servlets don’t have the package as a prefix.

   ...
   <plugin>
   	<groupId>com.totsp.gwt</groupId>
   	<artifactId>maven-googlewebtoolkit2-plugin</artifactId>
   	...
   	<configuration>
   		...
   		<webXmlServletPathAsIs>true</webXmlServletPathAsIs>
   	</configuration>
   	...
   </plugin>
   ...

3. Change your index.html file to point to your app.
   From:

   <meta http-equiv="REFRESH" content="0;url=my.long.package.name.Application/Application.html">

   To:

   <meta http-equiv="REFRESH" content="0;url=Application.html">

4. Your done.

Additional resources:
http://groups.google.com/group/Google-Web-Toolkit/browse_thread/thread/f8b06676098b8cc6

http://groups.google.com/group/gwt-maven/browse_thread/thread/a46f540ca823e3d3/7d5febf0776958db?lnk=gst&q=rename#7d5febf0776958db