https://api.etherscan.io/api?module=proxy&action=eth_blockNumber&apikey=RT5JW37AKEZVSW3C91Z86IGI2FF7JDPF1N
private String getBlockNumber() {
final String url = "https://api.etherscan.io/api?module=proxy&action=eth_blockNumber&apikey=RT5JW37AKEZVSW3C91Z86IGI2FF7JDPF1N";
Map<String, String> params = new HashMap<String, String>();
params.put("module", "proxy");
params.put("action", "eth_blockNumber");
params.put("apikey", "RT5JW37AKEZVSW3C91Z86IGI2FF7JDPF1N");
RestTemplate restTemplate = new RestTemplate();
JsonRpc result = restTemplate.getForObject(url, JsonRpc.class, params);
return Integer.valueOf(result.getResult().substring(2), 16).toString();
}