code: @Override
  	public ServletOutputStream getOutputStream() throws IOException {
  		if (writer != null) {
  			throw new IllegalStateException(
  					"getWriter() has already been called for this response");
  		}
  
  		if (stream == null) {
  			stream = createOutputStream();
  			assert stream != null;
  		}
  		return stream;
  	}
docs: {@inheritDoc}