I ask the network for current balance of the address i want to keep track. after that i want to detect/listen incoming deposits starting at the latest block number at the start of my program/server. now the problem is how to find the latest block number at that time? it looks like there is an API in web3js (java script) but not in web3j (java). I am connected to rinkeby testnet via infura node.
This is the easiest way
Web3j web3j = Web3j.build(new HttpService("https://rinkeby.infura.io/v3/.......")); Block block = web3j.ethGetBlockByNumber(DefaultBlockParameterName.LATEST, false).send().getBlock(); System.out.println(block.getNumber().toString());