refactoring: moved the password hashing into own class PasswordHasher.java

src/main/java/CreateUser.java

@@ -10,9 +10,6 @@ import java.util.List;
 import java.io.FileWriter;
 import java.io.IOException;
 
-import java.security.MessageDigest;
-import java.security.NoSuchAlgorithmException;
-
 import java.util.UUID;
 
 class CreateUser {
@@ -29,7 +26,7 @@ class CreateUser {
     public CreateUser(String id, String name, String password, String birthday, String firstName, String surname) {
     	this.id = id;
     	this.userName = name;
-    	this.password = hashPassword(password);
+    	this.password = PasswordHasher.hashPassword(password);;
     	this.birthday = birthday;
     	this.firstName = firstName;
     	this.surname = surname;
@@ -115,24 +112,6 @@ class CreateUser {
         }
     }
     
-    // Function to hash the password using SHA-256 algorithm
-    private String hashPassword(String password) {
-    	try {
-            MessageDigest digest = MessageDigest.getInstance("SHA-256");
-            byte[] hash = digest.digest(password.getBytes());
-            StringBuilder hexString = new StringBuilder();
-            for (byte b : hash) {
-                String hex = Integer.toHexString(0xff & b);
-                if (hex.length() == 1) hexString.append('0');
-                hexString.append(hex);
-            }
-            return hexString.toString();
-        } catch (NoSuchAlgorithmException e) {
-            e.printStackTrace();
-            return null;
-        }
-    }
-    
     // Function to save to JSON file, replace with database call later
     public void saveToJsonFile(String filename) {
     	List<CreateUser> userList = readUserListFromJsonFile(filename);

src/main/java/PasswordHasher.java

@@ -0,0 +1,21 @@
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+public class PasswordHasher {
+    public static String hashPassword(String password) {
+        try {
+            MessageDigest digest = MessageDigest.getInstance("SHA-256");
+            byte[] hash = digest.digest(password.getBytes());
+            StringBuilder hexString = new StringBuilder();
+            for (byte b : hash) {
+                String hex = Integer.toHexString(0xff & b);
+                if (hex.length() == 1) hexString.append('0');
+                hexString.append(hex);
+            }
+            return hexString.toString();
+        } catch (NoSuchAlgorithmException e) {
+            e.printStackTrace();
+            return null;
+        }
+    }
+}

src/main/java/SignUpGUI.java

@@ -5,6 +5,10 @@ import java.util.List;
 import java.util.UUID;
 
 public class SignUpGUI extends JFrame implements ActionListener {
+	/**
+	 * 
+	 */
+	private static final long serialVersionUID = 1L;
 	private JTextField usernameField, passwordField, confirmPasswordField, birthdayField, firstNameField, surnameField;
     private JButton signUpButton;
     

user.json

@@ -1,20 +1 @@
-[
-  {
-    "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
-  }
-]
+[]