@InvokeOnHeader(Web3jConstants.ETH_SIGN)
    void ethSign(Message message) throws IOException {
        String address = message.getHeader(Web3jConstants.ADDRESS, configuration::getAddress, String.class);
        String sha3HashOfDataToSign = message.getHeader(Web3jConstants.SHA3_HASH_OF_DATA_TO_SIGN,
                configuration::getSha3HashOfDataToSign, String.class);
        Request<?, EthSign> request = web3j.ethSign(address, sha3HashOfDataToSign);
        setRequestId(message, request);
        EthSign response = request.send();
        boolean hasError = checkForError(message, response);
        if (!hasError) {
            message.setBody(response.getSignature());
        }
    }
@Test
    public void ethSignTest() throws Exception {
        EthSign response = Mockito.mock(EthSign.class);
        Mockito.when(mockWeb3j.ethSign(any(), any())).thenReturn(request);
        Mockito.when(request.send()).thenReturn(response);
        Mockito.when(response.getSignature()).thenReturn("test");

        Exchange exchange = createExchangeWithBodyAndHeader(null, OPERATION, Web3jConstants.ETH_SIGN);
        template.send(exchange);
        String body = exchange.getIn().getBody(String.class);
        assertEquals("test", body);
    }