code: public void checkAndThrowException() throws Exception {
  		Throwable t = exception.get();
  		if (t != null) {
  			if (t instanceof Exception) {
  				throw (Exception) t;
  			}
  			else if (t instanceof Error) {
  				throw (Error) t;
  			}
  			else {
  				throw new Exception(t);
  			}
  		}
  	}
docs: Checks whether an exception has been set via {@link #reportError(Throwable)}.
  If yes, that exception if re-thrown by this method.
  
  @throws Exception This method re-throws the exception, if set.