wro4j-maven-plugin/src/main/java/ro/isdc/wro/maven/plugin/AbstractWro4jMojo.java
private void onAfterCreate(final WroManagerFactory factory)
      throws MojoExecutionException {
    if (factory instanceof ExtraConfigFileAware) {
      if (extraConfigFile == null) {
        throw new MojoExecutionException("The " + factory.getClass() + " requires a valid extraConfigFile!");
      }
      getLog().debug("Using extraConfigFile: " + extraConfigFile.getAbsolutePath());
      ((ExtraConfigFileAware) factory).setExtraConfigFile(extraConfigFile);
    }
    // initialize before process.
    if (factory instanceof StandaloneContextAware) {
      ((StandaloneContextAware) factory).initialize(createStandaloneContext());
    }
  }
private void onAfterCreate(final WroManagerFactory factory)
      throws MojoExecutionException {
    if (factory instanceof ExtraConfigFileAware) {
      if (extraConfigFile == null) {
        throw new MojoExecutionException("The " + factory.getClass() + " requires a valid extraConfigFile!");
      }
      getLog().debug("Using extraConfigFile: " + extraConfigFile.getAbsolutePath());
      ((ExtraConfigFileAware) factory).setExtraConfigFile(extraConfigFile);
    }
    // initialize before process.
    if (factory instanceof StandaloneContextAware) {
      ((StandaloneContextAware) factory).initialize(createStandaloneContext());
    }
  }
Initialize the created {@link WroManagerFactory} with additional configurations which are not available during
creation. Make sure this method is invoked on a custom factory when {@link #newWroManagerFactory()} is overridden.