私はサーバーに接続するために簡単なプログラムを使用しています:
はい、これ:
    public static void main(String[] args) throws Exception {
        String sentence;
        String modsent;
        //input Stream
        BufferedReader fromclient = new BufferedReader(new InputStreamReader(System.in));
        //client Socket
        Socket clientsock = new Socket("stockholm.serverdhse2.se", 9000);
        //output Stream attached to socket
        DataOutputStream serverout = new DataOutputStream(clientsock.getOutputStream());
        //input from Server
        BufferedReader fromserver = new BufferedReader(new InputStreamReader(clientsock.getInputStream()));
        sentence = fromclient.readLine();
        serverout.writeBytes(sentence + "\n");
        modsent = fromserver.readLine();
        System.out.println("From Server: " + modsent);
        clientsock.close();
    }
}
しかし、今は例外があります。
Exception in thread "main" java.net.ConnectException: Connection refused: connect
    at java.net.DualStackPlainSocketImpl.connect0(Native Method)
    at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
    at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
    at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
    at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
    at java.net.PlainSocketImpl.connect(Unknown Source)
    at java.net.SocksSocketImpl.connect(Unknown Source)
    at java.net.Socket.connect(Unknown Source)
    at java.net.Socket.connect(Unknown Source)
    at java.net.Socket.<init>(Unknown Source)
    at java.net.Socket.<init>(Unknown Source)
    at register.main(register.java:22)
何が問題なのですか?