diff --git a/spring-5-security/src/main/java/com/baeldung/loginextrafieldscustom/CustomAuthenticationToken.java b/spring-5-security/src/main/java/com/baeldung/loginextrafieldscustom/CustomAuthenticationToken.java
index 6de842f2e0..50995169a1 100644
--- a/spring-5-security/src/main/java/com/baeldung/loginextrafieldscustom/CustomAuthenticationToken.java
+++ b/spring-5-security/src/main/java/com/baeldung/loginextrafieldscustom/CustomAuthenticationToken.java
@@ -7,9 +7,7 @@ import org.springframework.security.core.GrantedAuthority;
 
 public class CustomAuthenticationToken extends UsernamePasswordAuthenticationToken {
 
-    private static final long serialVersionUID = 1L;
-
-    private final String domain;
+    private String domain;
 
     public CustomAuthenticationToken(Object principal, Object credentials, String domain) {
         super(principal, credentials);
diff --git a/spring-5-security/src/main/java/com/baeldung/loginextrafieldscustom/CustomUserDetailsAuthenticationProvider.java b/spring-5-security/src/main/java/com/baeldung/loginextrafieldscustom/CustomUserDetailsAuthenticationProvider.java
index 97a589077e..693900d843 100644
--- a/spring-5-security/src/main/java/com/baeldung/loginextrafieldscustom/CustomUserDetailsAuthenticationProvider.java
+++ b/spring-5-security/src/main/java/com/baeldung/loginextrafieldscustom/CustomUserDetailsAuthenticationProvider.java
@@ -19,8 +19,8 @@ public class CustomUserDetailsAuthenticationProvider extends AbstractUserDetails
      */
     private static final String USER_NOT_FOUND_PASSWORD = "userNotFoundPassword";
 
-    private final PasswordEncoder passwordEncoder;
-    private final CustomUserDetailsService userDetailsService;
+    private PasswordEncoder passwordEncoder;
+    private CustomUserDetailsService userDetailsService;
 
     /**
      * The password used to perform
diff --git a/spring-5-security/src/main/java/com/baeldung/loginextrafieldscustom/CustomUserDetailsServiceImpl.java b/spring-5-security/src/main/java/com/baeldung/loginextrafieldscustom/CustomUserDetailsServiceImpl.java
index bf53170205..ea979e2fab 100644
--- a/spring-5-security/src/main/java/com/baeldung/loginextrafieldscustom/CustomUserDetailsServiceImpl.java
+++ b/spring-5-security/src/main/java/com/baeldung/loginextrafieldscustom/CustomUserDetailsServiceImpl.java
@@ -8,7 +8,7 @@ import org.springframework.stereotype.Service;
 @Service("userDetailsService")
 public class CustomUserDetailsServiceImpl implements CustomUserDetailsService {
 
-    private final UserRepository userRepository;
+    private UserRepository userRepository;
  
     public CustomUserDetailsServiceImpl(UserRepository userRepository) {
         this.userRepository = userRepository;
diff --git a/spring-5-security/src/main/java/com/baeldung/loginextrafieldscustom/User.java b/spring-5-security/src/main/java/com/baeldung/loginextrafieldscustom/User.java
index 2d684d96e4..aa03f15b6a 100644
--- a/spring-5-security/src/main/java/com/baeldung/loginextrafieldscustom/User.java
+++ b/spring-5-security/src/main/java/com/baeldung/loginextrafieldscustom/User.java
@@ -8,7 +8,7 @@ public class User extends org.springframework.security.core.userdetails.User {
 
     private static final long serialVersionUID = 1L;
 
-    private final String domain;
+    private String domain;
 
     public User(String username, String domain, String password, boolean enabled, 
         boolean accountNonExpired, boolean credentialsNonExpired, 
diff --git a/spring-5-security/src/main/java/com/baeldung/loginextrafieldssimple/SimpleUserDetailsService.java b/spring-5-security/src/main/java/com/baeldung/loginextrafieldssimple/SimpleUserDetailsService.java
index 0b20c350b9..2fad50ad01 100644
--- a/spring-5-security/src/main/java/com/baeldung/loginextrafieldssimple/SimpleUserDetailsService.java
+++ b/spring-5-security/src/main/java/com/baeldung/loginextrafieldssimple/SimpleUserDetailsService.java
@@ -9,7 +9,7 @@ import org.springframework.stereotype.Service;
 @Service("userDetailsService")
 public class SimpleUserDetailsService implements UserDetailsService {
 
-    private final UserRepository userRepository;
+    private UserRepository userRepository;
  
     public SimpleUserDetailsService(UserRepository userRepository) {
         this.userRepository = userRepository;
diff --git a/spring-5-security/src/main/java/com/baeldung/loginextrafieldssimple/User.java b/spring-5-security/src/main/java/com/baeldung/loginextrafieldssimple/User.java
index 97b81f85e5..b76da65638 100644
--- a/spring-5-security/src/main/java/com/baeldung/loginextrafieldssimple/User.java
+++ b/spring-5-security/src/main/java/com/baeldung/loginextrafieldssimple/User.java
@@ -6,9 +6,7 @@ import org.springframework.security.core.GrantedAuthority;
 
 public class User extends org.springframework.security.core.userdetails.User {
 
-    private static final long serialVersionUID = 1L;
-
-    private final String domain;
+    private String domain;
 
     public User(String username, String domain, String password, boolean enabled, 
         boolean accountNonExpired, boolean credentialsNonExpired,