private void callBuildPlugin(File outputDir, String buildPluginClass) throws ClassNotFoundException, NoSuchMethodException, IllegalAccessException, InvocationTargetException {
        Class buildPlugin = Class.forName(buildPluginClass);
        try {
            Method method = buildPlugin.getMethod("addExtraFiles", File.class);
            method.invoke(null, outputDir);
            log.info("Extra files from %s extracted", buildPluginClass);
        } catch (NoSuchMethodException exp) {
            log.verbose(Logger.LogVerboseCategory.BUILD,"Build plugin %s does not support 'addExtraFiles' method", buildPluginClass);
        }
    }
Helper method to process an ImageConfiguration.

@param hub ServiceHub
@param aImageConfig ImageConfiguration that would be forwarded to build and tag
@throws DockerAccessException
@throws MojoExecutionException
src/main/java/io/fabric8/maven/docker/BuildMojo.java