java.net.SocketTimeoutException vs java.net.ConnectException

Question

When connecting to a server with a Java client socket I had this two different connection timeout exceptions.

Caused by: java.net.SocketTimeoutException: con         


        

Answer 1

ConnectException is thrown on packet filter/firewall etc.

SocketTimeoutException is thrown when you have set a specific timeout on your socket, and it has not received anything before the timeout.

Example with a ServerSocket:

ServerSocket serverSocket = new ServerSocket... // Create server socket
serverSocket.setSoTimeout(1000);  
serverSocket.accept();

If the ServerSocket has not received anything within 1000 ms it will throw a SocketTimeoutException. Note that this exception is thrown for all sockets that use timeouts, not only ServerSocket. This means that a Socket object that throws a SocketTimeoutException hasn't got anything back from the called server before the timeout.

To fix the problem you can either make sure that the server responds quicker, or set a higher timeout value.