Prevent writing in output area

src/main/java/ChatClient.java

@@ -24,6 +24,7 @@ public class ChatClient extends JFrame {
 
     private void initGui() {
         outputTextArea = new JTextArea();
+        outputTextArea.setEditable(false);
         outputTextArea.setBorder(BorderFactory.createTitledBorder("Chat"));
 
         inputTextField = new JTextField();