I would like to embed jppf-admin-web into my own embedded webserver as an executable jar. I need jppf-admin-web as a jar dependency instead of war to make this work. I would define my own web.xml for this and ignore the one inside

See description here: https://pragmaticintegrator.wordpress.com/2010/10/22/using-a-war-module-as-dependency-in-maven/

You would need to add:

<build>
...
 <plugins>
 ...
    <plugin>
     <artifactId>maven-war-plugin</artifactId>
     <version>${version.maven-war-plugin}</version>
     <configuration>
       <attachClasses>true</attachClasses>
     </configuration>
   </plugin>
 ...
 </plugins>
...
</build>

So that I could use:

<dependency>
  <groupId>org.jppf</groupId>
  <artifactId>jppf-admin-web</artifactId>
  <version>${version.jppf}</version>
  <classifier>classes</classifier>
</dependency>

Also it would be nice if you could define the jppf.css and and images/ as maven resources behind a package name and add those resources into the classes folder. You could then mount those resources in your wicket application under your current paths using PackageResourceReferences to serve them from the classpath. This makes embedding easier and I don't have to copy these resources myself then.