CODEWITHSUNDEEP
javasocketstcp
Mawia
Mawia

Reputation: 4310

Simple TCP Client-Server application throws exception

My TCP Server

public static void main(String argv[]) throws Exception {
    ServerSocket server = new ServerSocket(3333);
    System.out.println("Server started");
    while (true) {
      Socket socket = server.accept();
      BufferedReader input = new BufferedReader(new InputStreamReader(socket.getInputStream()));
      System.out.println("Received: " + input.readLine() + "\n");
    }
  }

My TCP Client.

 public static void main(String[] args) throws IOException {
    for (int i = 1; i < 50000; i++) {
      Socket clientSocket = new Socket("localhost", 3333);
      DataOutputStream outToServer = new DataOutputStream(clientSocket.getOutputStream());
      outToServer.writeBytes(i + "\n");
      clientSocket.close();
      System.out.println(i);
    }
  }

The loop in TCP client runs till 16374 and stopped, throwing this exception.

...
...
...
16372
16373
16374
Exception in thread "main" java.net.SocketException: No buffer space available (maximum connections reached?): connect
    at java.net.DualStackPlainSocketImpl.connect0(Native Method)
    at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:69)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:157)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:391)
    at java.net.Socket.connect(Socket.java:579)
    at java.net.Socket.connect(Socket.java:528)
    at java.net.Socket.<init>(Socket.java:425)
    at java.net.Socket.<init>(Socket.java:208)
    at mawia.test.Client.main(Test.java:11)
  1. What is wrong with my code?
  2. Why do I get this error?
  3. How to solve this problem?

Upvotes: 1

Views: 796

Answers (2)

kshirish
kshirish

Reputation: 1539

Also try once with adding flush() in your TCP Client code before closing the connection, worked with me.

Upvotes: 0

harsh
harsh

Reputation: 7692

Fildor is right, you are creating too many connections or Socket handles, this internally translates to allowed open-file-handles per process which in most probability you are breaking.

Ideal approach would be for client to keep on sending data (50000 records) on one connections i.e. Socket and Server should handle processing this data in a separate thread (So you can run multiple TCP Client concurrently):

TCP Server

public static void main(String argv[]) throws Exception {
        ServerSocket server = new ServerSocket(3333);
        System.out.println("Server started");
        while (true) {
          final Socket socket = server.accept();
          Thread t = new Thread(new Runnable() {
            public void run() {
                System.out.println("Server received message from client: ");
                BufferedReader input;
                try {
                    input = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                    while(!socket.isClosed() && socket.getInputStream().available() > 0){
                        System.out.println("Received: " + input.readLine() + "\n");
                    }
                    System.out.println("Client disconnected from server");
                } catch (IOException e) {
                    //break;
                }
            }
        });
          t.start();
        }
      }

TCP Client

public static void main(String[] args) throws IOException {
        Socket clientSocket = new Socket("localhost", 3333);
        for (int i = 1; i < 50000; i++) {
            DataOutputStream outToServer = new DataOutputStream(
                    clientSocket.getOutputStream());
            outToServer.writeBytes(i + "\n");
            outToServer.flush();
            System.out.println(i);
        }
        clientSocket.close();
    }

Upvotes: 2

Related Questions