refactoring: removed the hashing function in LoginGUI and replaced it with the PasswordHasher class

src/main/java/CreateUser.java

@@ -26,7 +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 = PasswordHasher.hashPassword(password);;
+    	this.password = PasswordHasher.hashPassword(password);
     	this.birthday = birthday;
     	this.firstName = firstName;
     	this.surname = surname;

src/main/java/LoginGUI.java

@@ -123,7 +123,7 @@ public class LoginGUI extends JFrame implements ActionListener {
         if (userList != null) {
         	for (CreateUser user : userList) {
                 if (user.getUserName().equals(username)) {
-                	String hashedPassword = hashPassword(password);
+                	String hashedPassword = PasswordHasher.hashPassword(password);
                 	if (user.getPassword().equals(hashedPassword)) {
                 		return true; 
                 	}
@@ -133,25 +133,6 @@ public class LoginGUI extends JFrame implements ActionListener {
         return false; 
     }
 
-    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;
-            }
-        }
-
     private class EnterKeyListener implements KeyListener {
         @Override
         public void keyTyped(KeyEvent e) {}

user.json

@@ -1 +1,11 @@
-[]
+[
+  {
+    "id": "c99b1061-13b7-4fa8-b1ac-814e07db3ef4",
+    "userName": "Test",
+    "password": "8d969eef6ecad3c29a3a629280e686cf0c3f5d5a86aff3ca12020c923adc6c92",
+    "birthday": "",
+    "firstName": "",
+    "surname": "",
+    "stayLoggedIn": false
+  }
+]