docs: public static boolean causedBy( final Throwable                     ex,
                                      final Class<? extends Throwable>    exceptionClass )
      {
          Throwable    cause = ex;
  
          while( cause != null && ! exceptionClass.isInstance( cause ) )
          {
              cause = cause.getCause();
          }
  
          return ( cause == null ) ? false : true;
      }