code: @Override
      public Throwable getRootCause(Throwable t)
      {
          if (t == null)
          {
              throw new NullPointerException("t");
          }
          
          while (t != null)
          {
              Class<?> clazz = t.getClass();
              if (!clazz.equals(FacesException.class) && !clazz.equals(ELException.class))
              {
                  return t;
              }
              
              t = t.getCause();
          }
          
          return null;
      }
docs: {@inheritDoc}