first phase

src/ChatArea.java

@@ -7,6 +7,7 @@ public class ChatArea extends JTextArea {
         super(ROWS, COLUMNS);
         this.setEditable(false);
         this.setLineWrap(true);
+        setVisible(true);
     }
 
     public void addMessage(String username, String message) {

src/ChatRoomGUI.java

@@ -17,6 +17,7 @@ public class ChatRoomGUI extends JFrame {
         this.setVisible(true);
         ChatArea chatBox = new ChatArea();
         this.add(new JScrollPane(chatBox), BorderLayout.CENTER);
+        chatBox.addMessage(" Ostad", " Hello!");
         MessageArea messageArea = new MessageArea();
         this.add(messageArea, BorderLayout.SOUTH);
         this.setVisible(true);
@@ -25,6 +26,7 @@ public class ChatRoomGUI extends JFrame {
         participantsArea.addNewParticipant(" Amirmehdy");
         participantsArea.addNewParticipant(" Abtin");
         participantsArea.removeParticipant(" Amirmehdy");
+        participantsArea.addNewParticipant(" Ostad");
         this.setVisible(true);
     }