diff --git a/src/main/java/LoginGUI.java b/src/main/java/LoginGUI.java
index a05d9ca..1c4ef8f 100644
--- a/src/main/java/LoginGUI.java
+++ b/src/main/java/LoginGUI.java
@@ -9,7 +9,11 @@ import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 
 public class LoginGUI extends JFrame implements ActionListener {
-    private JTextField usernameField;
+    /**
+	 * 
+	 */
+	private static final long serialVersionUID = 1L;
+	private JTextField usernameField;
     private JPasswordField passwordField;
     private JButton loginButton;
     private JCheckBox stayLoggedInCheckbox;
@@ -78,7 +82,6 @@ public class LoginGUI extends JFrame implements ActionListener {
         stayLoggedInCheckbox.addActionListener(e -> {
             boolean stayLoggedIn = stayLoggedInCheckbox.isSelected();
             String username = usernameField.getText();
-            // Set stayLoggedIn to false if the checkbox is unchecked
             if (!stayLoggedInCheckbox.isSelected()) {
                 stayLoggedIn = false;
             }
diff --git a/src/main/java/SignUpGUI.java b/src/main/java/SignUpGUI.java
index 696786b..70aa72f 100644
--- a/src/main/java/SignUpGUI.java
+++ b/src/main/java/SignUpGUI.java
@@ -96,35 +96,55 @@ public class SignUpGUI extends JFrame implements ActionListener {
 
     @Override
     public void actionPerformed(ActionEvent e) {
-    	if (e.getSource() == signUpButton) {
-    		String username = usernameField.getText();
-            String password = passwordField.getText();
-            String confirmPassword = confirmPasswordField.getText();
-            String birthday = birthdayField.getText();
-            String firstName = firstNameField.getText(); 
-            String surname = surnameField.getText();
-
-            if (!password.equals(confirmPassword)) {
-                JOptionPane.showMessageDialog(this, "Passwords do not match!", "Sign Up Error", JOptionPane.ERROR_MESSAGE);
-                return;
-            }
-            
-            if (!isUsernameAvailable("user.json", username)) {
-                JOptionPane.showMessageDialog(this, "Username already exists!", "Sign Up Error", JOptionPane.ERROR_MESSAGE);
-                return;
-            }
-            
-            try {
-                UUID randomUUID = UUID.randomUUID();
-                CreateUser user = CreateUser.createUser(randomUUID.toString(), username, password, birthday, firstName, surname);
-                user.saveToJsonFile("user.json");
-                JOptionPane.showMessageDialog(this, "User signed up successfully!");
-                dispose();
-            } catch (IllegalArgumentException ex) {
-                JOptionPane.showMessageDialog(this, "Error: " + ex.getMessage(), "Sign Up Error", JOptionPane.ERROR_MESSAGE);
-            }
+        if (e.getSource() == signUpButton) {
+            signUpUser();
+        }
+    }
+
+    private void signUpUser() {
+        String username = usernameField.getText();
+        String password = passwordField.getText();
+        String confirmPassword = confirmPasswordField.getText();
+        String birthday = birthdayField.getText();
+        String firstName = firstNameField.getText();
+        String surname = surnameField.getText();
+
+        if (!validatePasswordConfirmation(password, confirmPassword)) {
+            showErrorMessage("Passwords do not match!");
+            return;
+        }
+
+        if (!isUsernameAvailable("user.json", username)) {
+            showErrorMessage("Username already exists!");
+            return;
+        }
+
+        try {
+            createUserAndSave(username, password, birthday, firstName, surname);
+            showSuccessMessage("User signed up successfully!");
+            dispose();
+        } catch (IllegalArgumentException ex) {
+            showErrorMessage("Error: " + ex.getMessage());
         }
     }
+
+    private boolean validatePasswordConfirmation(String password, String confirmPassword) {
+        return password.equals(confirmPassword);
+    }
+
+    private void showErrorMessage(String message) {
+        JOptionPane.showMessageDialog(this, message, "Sign Up Error", JOptionPane.ERROR_MESSAGE);
+    }
+
+    private void showSuccessMessage(String message) {
+        JOptionPane.showMessageDialog(this, message);
+    }
+
+    private void createUserAndSave(String username, String password, String birthday, String firstName, String surname) {
+        UUID randomUUID = UUID.randomUUID();
+        CreateUser user = CreateUser.createUser(randomUUID.toString(), username, password, birthday, firstName, surname);
+        user.saveToJsonFile("user.json");
+    }
     
     // Function to check if the input username doesn't already exist in the JSON file
     private boolean isUsernameAvailable(String filename, String username) {
diff --git a/user.json b/user.json
index 0637a08..cfc325c 100644
--- a/user.json
+++ b/user.json
@@ -1 +1,20 @@
-[]
\ No newline at end of file
+[
+  {
+    "id": "e365e96f-6c6c-48e5-96e0-7b5e058e7198",
+    "userName": "existinguser",
+    "password": "5e884898da28047151d0e56f8dc6292773603d0d6aabbdd62a11ef721d1542d8",
+    "birthday": "1990-01-01",
+    "firstName": "John",
+    "surname": "Doe",
+    "stayLoggedIn": false
+  },
+  {
+    "id": "61ef4208-9077-42c4-983f-f1e234f7e5f4",
+    "userName": "testUser",
+    "password": "5e884898da28047151d0e56f8dc6292773603d0d6aabbdd62a11ef721d1542d8",
+    "birthday": "1990-01-01",
+    "firstName": "John",
+    "surname": "Doe",
+    "stayLoggedIn": false
+  }
+]
\ No newline at end of file