NIO client giving exception : java.net.ConnectException: Connection refused: no further information

Question

I modified the sample code available here for Client and Server My client :

public class Client {

public static void main(String[] args) {

    int n=10000;         


        

Answer 1

I believe the ConnectException you are getting with 500 threads is not coming from SocketTest.connect(). It could be coming from any of the other IO methods.

For a quick fix (and to convince yourself), you can explicitly catch ConnectException in your main try-catch block like this:

try {
    // connect, write, and read ...
} catch (ConnectException ce) {  // <-- catch the more specific Exception first
    System.out.println("You caught a ConnectException.");
} catch (IOException e1) {       // <-- you originally only caught this
    // TODO Auto-generated catch block
    e1.printStackTrace();
} finally {

As to why this is happening, I can tell you that I am currently ramping up to hundreds of threads for testing a SOAP service. I also get dropped connections all over the place, so maybe this is to be expected with such a large number of concurrent threads.