@InvokeOnHeader(Web3jConstants.ETH_BLOCK_NUMBER)
    void ethBlockNumber(Message message) throws IOException {
        Request<?, EthBlockNumber> request = web3j.ethBlockNumber();
        setRequestId(message, request);
        EthBlockNumber response = request.send();
        boolean hasError = checkForError(message, response);
        if (!hasError) {
            message.setBody(response.getBlockNumber());
        }
    }
@Test
    public void ethBlockNumberTest() throws Exception {
        EthBlockNumber response = Mockito.mock(EthBlockNumber.class);
        Mockito.when(mockWeb3j.ethBlockNumber()).thenReturn(request);
        Mockito.when(request.send()).thenReturn(response);
        Mockito.when(response.getBlockNumber()).thenReturn(BigInteger.ONE);

        Exchange exchange = createExchangeWithBodyAndHeader(null, OPERATION, Web3jConstants.ETH_BLOCK_NUMBER);
        template.send(exchange);
        BigInteger body = exchange.getIn().getBody(BigInteger.class);
        assertEquals(BigInteger.ONE, body);
    }