wro4j-maven-plugin/src/main/java/ro/isdc/wro/maven/plugin/AbstractWro4jMojo.java
private WroManagerFactory createCustomManagerFactory()
      throws MojoExecutionException {
    WroManagerFactory factory = null;
    try {
      final Class<?> wroManagerFactoryClass = Thread.currentThread().getContextClassLoader().loadClass(
          wroManagerFactory.trim());
      factory = (WroManagerFactory) wroManagerFactoryClass.newInstance();
    } catch (final Exception e) {
      throw new MojoExecutionException("Invalid wroManagerFactoryClass, called: " + wroManagerFactory, e);
    }
    return factory;
  }
private WroManagerFactory createCustomManagerFactory()
      throws MojoExecutionException {
    WroManagerFactory factory = null;
    try {
      final Class<?> wroManagerFactoryClass = Thread.currentThread().getContextClassLoader().loadClass(
          wroManagerFactory.trim());
      factory = (WroManagerFactory) wroManagerFactoryClass.newInstance();
    } catch (final Exception e) {
      throw new MojoExecutionException("Invalid wroManagerFactoryClass, called: " + wroManagerFactory, e);
    }
    return factory;
  }
Creates a custom instance of Manager factory. The wroManagerFactory parameter value is used to identify the manager class.