code: public Source getSource() {
      try {
        return Source.class.cast(Class.forName(this.taskState.getProp(ConfigurationKeys.SOURCE_CLASS_KEY)).newInstance());
      } catch (ClassNotFoundException cnfe) {
        throw new RuntimeException(cnfe);
      } catch (InstantiationException ie) {
        throw new RuntimeException(ie);
      } catch (IllegalAccessException iae) {
        throw new RuntimeException(iae);
      }
    }
docs: Get a {@link Source} instance used to get a list of {@link WorkUnit}s.
  
  @return the {@link Source} used to get the {@link WorkUnit}, <em>null</em>
  if it fails to instantiate a {@link Source} object of the given class.