public T send() throws IOException {
        return web3jService.send(this, responseType);
    }
@Test
    public void testEthSign() throws Exception {
        web3j.ethSign(
                        "0x8a3106a3e50576d4b6794a0e74d3bb5f8c9acaab",
                        "0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470")
                .send();

        verifyResult(
                "{\"jsonrpc\":\"2.0\",\"method\":\"eth_sign\","
                        + "\"params\":[\"0x8a3106a3e50576d4b6794a0e74d3bb5f8c9acaab\","
                        + "\"0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470\"],"
                        + "\"id\":1}");
    }