Added an if statement in the action listener for the checkbox in LoginGUI so the stayLoggedIn variable gets also changed when the checkbox is unticked

src/main/java/LoginGUI.java

@@ -51,6 +51,10 @@ public class LoginGUI extends JFrame implements ActionListener {
             public void actionPerformed(ActionEvent e) {
                 boolean stayLoggedIn = stayLoggedInCheckbox.isSelected();
                 String username = usernameField.getText();
+             // Set stayLoggedIn to false if the checkbox is unchecked
+                if (!stayLoggedInCheckbox.isSelected()) {
+                stayLoggedIn = false;
+                }
                 updateStayLoggedIn(username, stayLoggedIn);
             }
         });

user.json

@@ -18,6 +18,6 @@
     "userName": "Test User",
     "password": "Test",
     "birthday": "01.01.2000",
-    "stayLoggedIn": true
+    "stayLoggedIn": false
   }
 ]