[FIXED] java.lang.ClassCastException: class org.springframework.security.core.userdetails.User cannot be cast to class

Issue

I have a problem with my spring boot application. I'm sending a request to get the key, but i get an error

java.lang.ClassCastException: class org.springframework.security.core.userdetails.User cannot be cast to class com.spring.springBlogProject.model.User (org.springframework.security.core.userdetails.User and com.spring.springBlogProject.model.User are in unnamed module of loader 'app')
    at com.spring.springBlogProject.security.JwtProvider.generateToken(JwtProvider.java:28) ~[classes/:na]

I can’t understand what the problem is, I work with spring for the first time. I see that the received data cannot be reduced to the class that I created. What could be the problem? Below are my classes, I'm using Spring Boot (v2.3.1.RELEASE)

Thanks for your help.

public class UserDetailsServiceImpl implements UserDetailsService {

    @Autowired
    private UserRepository userRepository;

    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
       User user = userRepository.findByUsername(username).orElseThrow(()->
                new UsernameNotFoundException("No user found with " + username));

        return new org.springframework.security.core.userdetails.User(user.getUsername(),
                user.getPassword(),
                true,true,true,true,
                getAuthorities("ROLE_USER"));
    }

    private Collection<? extends GrantedAuthority> getAuthorities(String role_user) {
        return Collections.singletonList(new SimpleGrantedAuthority(role_user));
    }
}

@Table
public class User {
    @Id
    @GeneratedValue (strategy = GenerationType.IDENTITY)
    private Long id;

    @Column
    private String username;

    @Column
    private String password;

    @Column
    private String email;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }
}

public class AuthService {

    @Autowired
    private UserRepository userRepository;
    @Autowired
    private PasswordEncoder passwordEncoder;
    @Autowired
    private AuthenticationManager authenticationManager;
    @Autowired
    private JwtProvider jwtProvider;

    public void signUp(RegisterRequest registerRequest) {
        User user = new User();
        user.setUsername(registerRequest.getUsername());
        user.setPassword(encodePassword(registerRequest.getPassword()));
        user.setEmail(registerRequest.getEmail());

        userRepository.save(user);
    }

    private String encodePassword(String password) {
        return passwordEncoder.encode(password);
    }

    public String login(LoginRequest loginRequest) {
       Authentication authenticate =  authenticationManager.authenticate(new UsernamePasswordAuthenticationToken(loginRequest.getUsername(),
                loginRequest.getPassword()));
        SecurityContextHolder.getContext().setAuthentication(authenticate);
        return jwtProvider.generateToken(authenticate);
    }
}

Solution

You have to convert it in UserDetails following way,

public class JwtUser implements UserDetails {

    private final long id;
    private final String email;
    private final String phoneNo;
    private final String username;
    private final String password;
    private final boolean enabled;
    private final Collection<? extends GrantedAuthority> authorities;

    public JwtUser(long userId, String email, String username, String phoneNo, String password, Boolean enabled,  Collection<? extends GrantedAuthority> authorities) {
        this.id = userId;
        this.email = email;
        this.phoneNo = phoneNo;
        this.username = username;
        this.password = password;
        this.enabled = enabled;
        this.authorities = authorities;
    }

    public long getId() {
        return id;
    }

    public String getEmail() {
        return email;
    }

    public String getPhoneNo() {
        return phoneNo;
    }

    @Override
    public Collection<? extends GrantedAuthority> getAuthorities() {
        return authorities;
    }

    @Override
    public String getPassword() {
        return password;
    }

    @Override
    public String getUsername() {
        return username;
    }

    @Override
    public boolean isAccountNonExpired() {
        return true;
    }

    @Override
    public boolean isAccountNonLocked() {
        return true;
    }

    @Override
    public boolean isCredentialsNonExpired() {
        return true;
    }

    @Override
    public boolean isEnabled() {
        return enabled;
    }
}

Replace :

return new org.springframework.security.core.userdetails.User(user.getUsername(),
                user.getPassword(),
                true,true,true,true,
                getAuthorities("ROLE_USER"));

with :

return new JwtUser(user.get().getUserId(), user.get().getEmail(), user.get().getUsername(),
                user.get().getPhoneNo(), user.get().getPassword(), Boolean.TRUE, grantedAuthoritySet(user.get().getAuthorities()));

Answered By - Dhwanil Patel