Refactor: Create variable for connection failed message

src/main/java/ChatClient.java

@@ -7,6 +7,7 @@ import java.net.Socket;
 
 public class ChatClient extends JFrame implements KeyListener {
     private String address;
+    private String connectionFailedMessage;
     private Socket connectionToServer;
     private BufferedReader fromServerReader;
     private PrintWriter toServerWriter;
@@ -19,8 +20,8 @@ public class ChatClient extends JFrame implements KeyListener {
     public ChatClient() {
         super("Chat");
         address = JOptionPane.showInputDialog("bitte IP-Adresse");
-        
         if (null != address) {
+            connectionFailedMessage = "Verbindung zum Server " + (address.isEmpty() ? "" : ("\"" + address + "\"")) + " fehlgeschlagen.";
             receiveMessages();
         }
     }
@@ -58,7 +59,7 @@ public class ChatClient extends JFrame implements KeyListener {
                 outputScrollPane.getVerticalScrollBar().setValue(outputScrollPane.getVerticalScrollBar().getMaximum());
             }
         } catch (IOException e) {
-            JOptionPane.showMessageDialog(null, "Verbindung zum Server \"" + address + "\" fehlgeschlagen.");
+            JOptionPane.showMessageDialog(null, connectionFailedMessage);
             dispose();
         } finally {
             if (null != connectionToServer) {