Issues sending Ether with web3j

Question

Hello guys I have search around but no reasonable explanation as to why i would get these exceptions, I have already requested and have 3 ethers with associated with my address. Here is my code for sending ether:

private static void transferEther(String password)
            throws IOException, CipherException, InterruptedException, TransactionException {
        Web3j web3 = Web3j.build(new HttpService("https://rinkeby.infura.io/v1/<API-KEY>"));

    Web3ClientVersion web3ClientVersion = web3.web3ClientVersion().send();
    String clientVersion = web3ClientVersion.getWeb3ClientVersion();
    System.out.println("Connected to Ethereum client version: " + clientVersion);

    Credentials credentials = WalletUtils.loadCredentials(password,
            new File("/PATH_TO_FILE/"
                    + "UTC--2018-12-12T07-39-27.54000000Z--ff1062eb9f9f4369780f8029fe60a5825eb943c9.json")
                            .toString());

    RemoteCall<TransactionReceipt> transactionReceipt = Transfer.sendFunds(web3, credentials,
            "ADDRESS", BigDecimal.valueOf(0.2), Convert.Unit.ETHER);

    System.out.println("Funds transfer completed, transaction hash: " + transactionReceipt.toString());
}

but i get the following exceptions:

Exception in thread "main" java.lang.NoClassDefFoundError: rx/schedulers/Schedulers at org.web3j.protocol.rx.JsonRpc2_0Rx.(JsonRpc2_0Rx.java:39) at org.web3j.protocol.core.JsonRpc2_0Web3j.(JsonRpc2_0Web3j.java:87) at org.web3j.protocol.core.JsonRpc2_0Web3j.(JsonRpc2_0Web3j.java:80) at org.web3j.protocol.Web3j.build(Web3j.java:21) at CreateWallet.transferEther(CreateWallet.java:51) at CreateWallet.main(CreateWallet.java:81) Caused by: java.lang.ClassNotFoundException: rx.schedulers.Schedulers at java.net.URLClassLoader.findClass(URLClassLoader.java:381) at java.lang.ClassLoader.loadClass(ClassLoader.java:424) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ... 6 more

Answer 1

In case anyone had this problem I found the solution. It was simply a proxy problem and missing library problem.

1. add the rxJava ,okio and Okhttp jar lib.

2. This step is optional if u have a proxy problem like i did.

   String hostname = "IP ADDRESS";
   int port = PORT;
   
   Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress(hostname, port));
   OkHttpClient client = new OkHttpClient.Builder().proxy(proxy).build();
   
   String url = "https://rinkeby.infura.io/v3/<API-KEY>";
   
   web3 = Web3j.build(new HttpService(url, client, true));