How to close ServerSocket connection when catching IOException?

Question

Sorry for question, but I\'m totally noob in Java. What is the best practice to execute ServerSocket.close() when caught IOException from Ser

Answer 1

If you are going to close the ServerSocket outside of the try{}catch{} anyways, you may as well put it in a finally{}

try {
    server = new ServerSocket(this.getServerPort());
    while(true) {
        socket = server.accept();
        new Handler( socket );
    }
} catch (IOException e) {
    // Do whatever you need to do here, like maybe deal with "socket"?
}
finally {
    try {  
        server.close();
    } catch(Exception e) {
        // If you really want to know why you can't close the ServerSocket, like whether it's null or not
    }
}

Answer 2

That's ugly in Java. I hate it, but this is the way you should do it: Wrapping it into another try-catch:

try {
    server = new ServerSocket(this.getServerPort());
    while(true) {
        socket = server.accept();
        new Handler( socket );
    }
} catch (IOException e) {
    if (server != null && !server.isClosed()) {
        try {
            server.close();
        } catch (IOException e)
        {
            e.printStackTrace(System.err);
        }
    }
}

Answer 3

You can close the resources in the finally block,

http://download.oracle.com/javase/tutorial/essential/exceptions/finally.html

 } finally {
      try {
        socket.close();
      } catch(IOException e) {
         e.printStackTrace(); 
      }
}

Answer 4

In Java SE 7 or later you can use try-with-resources statement, ServerSocket implements java.io.Closeable, so you don't need to explicitly #close() the socket when used in this way.

try (ServerSocket server = new ServerSocket(this.getServerPort())) {
    while(true) {
        socket = server.accept();
        new Handler( socket );
    }
} catch (IOException e) {
    // It's already closed, just print the exception
    System.out.println(e);
}