Spring Boot JWT Security

Comprehensive JWT (JSON Web Token) authentication and authorization patterns for Spring Boot 3.5.x applications using Spring Security 6.x and the JJWT library. This skill provides production-ready implementations for stateless authentication, role-based access control, and integration with modern authentication providers.

Overview

JWT authentication enables stateless, scalable security for Spring Boot applications. This skill covers complete JWT lifecycle management including token generation, validation, refresh strategies, and integration patterns with database-backed and OAuth2 authentication providers. Implementations follow Spring Security 6.x best practices with modern SecurityFilterChain configuration.

When to Use

Use this skill when:

• Implementing stateless authentication for REST APIs
• Building SPA (Single Page Application) backends with JWT
• Securing microservices with token-based authentication
• Integrating with OAuth2 providers (Google, GitHub, etc.)
• Implementing role-based or permission-based access control
• Setting up JWT refresh token strategies
• Migrating from session-based to token-based authentication
• Building mobile API backends
• Implementing cross-origin authentication with CORS

Prerequisites

• Java 17+ (for records and pattern matching)
• Spring Boot 3.5.x (for Spring Security 6.x integration)
• JJWT library (io.jsonwebtoken) for JWT operations
• Maven or Gradle build system
• Basic understanding of Spring Security concepts

Dependencies

Maven

<dependencies>
    <!-- Spring Security -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-security</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-validation</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-oauth2-resource-server</artifactId>
    </dependency>

    <!-- JWT Library -->
    <dependency>
        <groupId>io.jsonwebtoken</groupId>
        <artifactId>jjwt-api</artifactId>
        <version>0.12.6</version>
    </dependency>
    <dependency>
        <groupId>io.jsonwebtoken</groupId>
        <artifactId>jjwt-impl</artifactId>
        <version>0.12.6</version>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>io.jsonwebtoken</groupId>
        <artifactId>jjwt-jackson</artifactId>
        <version>0.12.6</version>
        <scope>runtime</scope>
    </dependency>

    <!-- Database -->
    <dependency>
        <groupId>com.h2database</groupId>
        <artifactId>h2</artifactId>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>org.postgresql</groupId>
        <artifactId>postgresql</artifactId>
        <scope>runtime</scope>
    </dependency>

    <!-- Testing -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework.security</groupId>
        <artifactId>spring-security-test</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.testcontainers</groupId>
        <artifactId>junit-jupiter</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework.security</groupId>
        <artifactId>spring-security-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

Gradle

dependencies {
    // Spring Security
    implementation("org.springframework.boot:spring-boot-starter-security")
    implementation("org.springframework.boot:spring-boot-starter-web")
    implementation("org.springframework.boot:spring-boot-starter-data-jpa")
    implementation("org.springframework.boot:spring-boot-starter-validation")
    implementation("org.springframework.boot:spring-boot-starter-oauth2-resource-server")

    // JWT Library
    implementation("io.jsonwebtoken:jjwt-api:0.12.6")
    implementation("io.jsonwebtoken:jjwt-impl:0.12.6")
    implementation("io.jsonwebtoken:jjwt-jackson:0.12.6")

    // Database
    runtimeOnly("com.h2database:h2")
    runtimeOnly("org.postgresql:postgresql")

    // Testing
    testImplementation("org.springframework.boot:spring-boot-starter-test")
    testImplementation("org.springframework.security:spring-security-test")
    testImplementation("org.testcontainers:junit-jupiter")
}

Quick Start

1. Application Configuration

# application.yml
spring:
  security:
    oauth2:
      client:
        registration:
          google:
            client-id: ${GOOGLE_CLIENT_ID}
            client-secret: ${GOOGLE_CLIENT_SECRET}
            scope: openid, profile, email

jwt:
  secret: ${JWT_SECRET:my-very-secret-key-that-is-at-least-256-bits-long}
  access-token-expiration: 86400000    # 24 hours in milliseconds
  refresh-token-expiration: 604800000 # 7 days in milliseconds
  issuer: spring-boot-jwt-example
  cookie-name: jwt-token
  cookie-secure: false                 # Set to true in production with HTTPS
  cookie-http-only: true
  cookie-same-site: lax

2. Modern Spring Security 6.x Configuration

@Configuration
@EnableWebSecurity
@EnableMethodSecurity
@RequiredArgsConstructor
public class SecurityConfig {

    private final JwtAuthenticationFilter jwtAuthFilter;
    private final AuthenticationProvider authenticationProvider;
    private final LogoutHandler logoutHandler;

    @Bean
    public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
        http
            .csrf(csrf -> csrf.disable())
            .cors(cors -> cors.configurationSource(corsConfigurationSource()))
            .sessionManagement(session -> session.sessionCreationPolicy(SessionCreationPolicy.STATELESS))
            .authorizeHttpRequests(authz -> authz
                .requestMatchers("/api/auth/**").permitAll()
                .requestMatchers("/api/public/**").permitAll()
                .requestMatchers(HttpMethod.GET, "/api-docs/**").permitAll()
                .requestMatchers(HttpMethod.GET, "/swagger-ui/**").permitAll()
                .anyRequest().authenticated()
            )
            .authenticationProvider(authenticationProvider)
            .addFilterBefore(jwtAuthFilter, UsernamePasswordAuthenticationFilter.class)
            .logout(logout -> logout
                .logoutUrl("/api/auth/logout")
                .addLogoutHandler(logoutHandler)
                .logoutSuccessHandler((request, response, authentication) ->
                    SecurityContextHolder.clearContext())
            );

        return http.build();
    }

    @Bean
    public CorsConfigurationSource corsConfigurationSource() {
        CorsConfiguration configuration = new CorsConfiguration();
        configuration.setAllowedOriginPatterns(List.of("*"));
        configuration.setAllowedMethods(List.of("GET", "POST", "PUT", "DELETE", "OPTIONS"));
        configuration.setAllowedHeaders(List.of("*"));
        configuration.setAllowCredentials(true);

        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        source.registerCorsConfiguration("/**", configuration);
        return source;
    }
}

3. JWT Service Implementation

@Service
@RequiredArgsConstructor
@Slf4j
public class JwtService {

    @Value("${jwt.secret}")
    private String secret;

    @Value("${jwt.access-token-expiration}")
    private long accessTokenExpiration;

    @Value("${jwt.refresh-token-expiration}")
    private long refreshTokenExpiration;

    @Value("${jwt.issuer}")
    private String issuer;

    private final RefreshTokenService refreshTokenService;

    /**
     * Generate access token for user
     */
    public String generateAccessToken(UserDetails userDetails) {
        return generateToken(userDetails, accessTokenExpiration);
    }

    /**
     * Generate refresh token for user
     */
    public String generateRefreshToken(UserDetails userDetails) {
        return refreshTokenService.createRefreshToken(userDetails.getUsername());
    }

    /**
     * Extract username from JWT token
     */
    public String extractUsername(String token) {
        return extractClaims(token).getSubject();
    }

    /**
     * Extract claims from JWT token
     */
    private Claims extractClaims(String token) {
        return Jwts.parser()
                .verifyWith(getSigningKey())
                .build()
                .parseSignedClaims(token)
                .getPayload();
    }

    /**
     * Validate JWT token
     */
    public boolean isTokenValid(String token, UserDetails userDetails) {
        try {
            final String username = extractUsername(token);
            return (username.equals(userDetails.getUsername()) &&
                    !isTokenExpired(token) &&
                    extractClaims(token).getIssuer().equals(issuer));
        } catch (JwtException | IllegalArgumentException e) {
            log.debug("Invalid JWT token: {}", e.getMessage());
            return false;
        }
    }

    /**
     * Check if token is expired
     */
    private boolean isTokenExpired(String token) {
        return extractClaims(token).getExpiration().before(new Date());
    }

    /**
     * Generate token with expiration
     */
    private String generateToken(UserDetails userDetails, long expiration) {
        Date now = new Date();
        Date expiryDate = new Date(now.getTime() + expiration);

        return Jwts.builder()
                .setSubject(userDetails.getUsername())
                .setIssuer(issuer)
                .setIssuedAt(now)
                .setExpiration(expiryDate)
                .claim("authorities", getAuthorities(userDetails))
                .claim("type", "access")
                .signWith(getSigningKey())
                .compact();
    }

    /**
     * Get signing key from secret
     */
    private SecretKey getSigningKey() {
        byte[] keyBytes = secret.getBytes(StandardCharsets.UTF_8);
        return Keys.hmacShaKeyFor(keyBytes);
    }

    /**
     * Extract authorities from user details
     */
    private List<String> getAuthorities(UserDetails userDetails) {
        return userDetails.getAuthorities().stream()
                .map(GrantedAuthority::getAuthority)
                .collect(Collectors.toList());
    }
}

3. JWT Authentication Filter

@Component
@RequiredArgsConstructor
public class JwtAuthenticationFilter extends OncePerRequestFilter {

    private final JwtService jwtService;
    private final UserDetailsService userDetailsService;

    @Override
    protected void doFilterInternal(
            @NonNull HttpServletRequest request,
            @NonNull HttpServletResponse response,
            @NonNull FilterChain filterChain) throws ServletException, IOException {

        final String authHeader = request.getHeader("Authorization");
        final String jwt;
        final String userEmail;

        // Check for Bearer token
        if (authHeader == null || !authHeader.startsWith("Bearer ")) {
            // Check for JWT cookie
            String jwtCookie = WebUtils.getCookie(request, "jwt-token") != null
                ? WebUtils.getCookie(request, "jwt-token").getValue()
                : null;

            if (jwtCookie != null) {
                jwt = jwtCookie;
                userEmail = jwtService.extractUsername(jwt);

                if (userEmail != null && SecurityContextHolder.getContext().getAuthentication() == null) {
                    UserDetails userDetails = userDetailsService.loadUserByUsername(userEmail);

                    if (jwtService.isTokenValid(jwt, userDetails)) {
                        UsernamePasswordAuthenticationToken authToken =
                            new UsernamePasswordAuthenticationToken(
                                userDetails,
                                null,
                                userDetails.getAuthorities()
                            );
                        authToken.setDetails(
                            new WebAuthenticationDetailsSource().buildDetails(request)
                        );
                        SecurityContextHolder.getContext().setAuthentication(authToken);
                    }
                }
            }

            filterChain.doFilter(request, response);
            return;
        }

        jwt = authHeader.substring(7);
        userEmail = jwtService.extractUsername(jwt);

        if (userEmail != null && SecurityContextHolder.getContext().getAuthentication() == null) {
            UserDetails userDetails = userDetailsService.loadUserByUsername(userEmail);

            if (jwtService.isTokenValid(jwt, userDetails)) {
                UsernamePasswordAuthenticationToken authToken =
                    new UsernamePasswordAuthenticationToken(
                        userDetails,
                        null,
                        userDetails.getAuthorities()
                    );
                authToken.setDetails(
                    new WebAuthenticationDetailsSource().buildDetails(request)
                );
                SecurityContextHolder.getContext().setAuthentication(authToken);
            }
        }

        filterChain.doFilter(request, response);
    }
}

4. Security Configuration

@Configuration
@EnableWebSecurity
@RequiredArgsConstructor
@EnableMethodSecurity(prePostEnabled = true)
public class SecurityConfig {

    private final JwtAuthenticationFilter jwtAuthFilter;
    private final AuthenticationProvider authenticationProvider;
    private final LogoutHandler logoutHandler;

    @Bean
    public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
        http
            .csrf(AbstractHttpConfigurer::disable)
            .authorizeHttpRequests(auth -> auth
                // Public endpoints
                .requestMatchers("/api/v1/auth/**").permitAll()
                .requestMatchers("/api/v1/oauth2/**").permitAll()
                .requestMatchers("/swagger-ui/**", "/v3/api-docs/**").permitAll()
                .requestMatchers("/health").permitAll()

                // Admin endpoints
                .requestMatchers("/api/v1/admin/**").hasRole("ADMIN")

                // Protected endpoints
                .anyRequest().authenticated()
            )
            .sessionManagement(sess -> sess
                .sessionCreationPolicy(SessionCreationPolicy.STATELESS)
            )
            .authenticationProvider(authenticationProvider)
            .addFilterBefore(jwtAuthFilter, UsernamePasswordAuthenticationFilter.class)
            .oauth2Login(oauth2 -> oauth2
                .loginPage("/oauth2/authorization/google")
                .defaultSuccessUrl("/api/v1/auth/oauth2/success", true)
                .failureUrl("/api/v1/auth/oauth2/failure")
            )
            .logout(logout -> logout
                .logoutUrl("/api/v1/auth/logout")
                .addLogoutHandler(logoutHandler)
                .logoutSuccessHandler((request, response, authentication) ->
                    SecurityContextHolder.clearContext())
            );

        return http.build();
    }

    @Bean
    public AuthenticationProvider authenticationProvider(UserDetailsService userDetailsService, PasswordEncoder passwordEncoder) {
        DaoAuthenticationProvider authProvider = new DaoAuthenticationProvider();
        authProvider.setUserDetailsService(userDetailsService);
        authProvider.setPasswordEncoder(passwordEncoder);
        return authProvider;
    }

    @Bean
    public PasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }

    @Bean
    public AuthenticationManager authenticationManager(AuthenticationConfiguration config) throws Exception {
        return config.getAuthenticationManager();
    }
}

Authentication Controllers

@RestController
@RequestMapping("/api/v1/auth")
@RequiredArgsConstructor
@Slf4j
public class AuthenticationController {

    private final AuthenticationService authenticationService;

    @PostMapping("/register")
    public ResponseEntity<AuthenticationResponse> register(
            @Valid @RequestBody RegisterRequest request) {
        log.info("Registering new user: {}", request.getEmail());
        return ResponseEntity.ok(authenticationService.register(request));
    }

    @PostMapping("/authenticate")
    public ResponseEntity<AuthenticationResponse> authenticate(
            @Valid @RequestBody AuthenticationRequest request) {
        log.info("Authenticating user: {}", request.getEmail());
        AuthenticationResponse response = authenticationService.authenticate(request);

        return ResponseEntity.ok()
                .header("Set-Cookie", createJwtCookie(response.getAccessToken()))
                .body(response);
    }

    @PostMapping("/refresh")
    public ResponseEntity<AuthenticationResponse> refreshToken(
            @RequestBody RefreshTokenRequest request) {
        log.info("Refreshing token for user");
        return ResponseEntity.ok(authenticationService.refreshToken(request));
    }

    @GetMapping("/me")
    public ResponseEntity<UserProfile> getCurrentUser() {
        return ResponseEntity.ok(authenticationService.getCurrentUser());
    }

    private String createJwtCookie(String token) {
        return String.format(
            "jwt-token=%s; Path=/; HttpOnly; SameSite=Lax; Max-Age=%d",
            token,
            86400 // 24 hours
        );
    }
}

Authorization Patterns

Role-Based Access Control (RBAC)

@RestController
@RequestMapping("/api/v1/admin")
@RequiredArgsConstructor
@PreAuthorize("hasRole('ADMIN')")
public class AdminController {

    private final AdminService adminService;

    @GetMapping("/users")
    @PreAuthorize("hasAuthority('ADMIN_READ')")
    public ResponseEntity<Page<UserResponse>> getAllUsers(Pageable pageable) {
        return ResponseEntity.ok(adminService.getAllUsers(pageable));
    }

    @DeleteMapping("/users/{id}")
    @PreAuthorize("hasAuthority('ADMIN_DELETE')")
    public ResponseEntity<Void> deleteUser(@PathVariable Long id) {
        adminService.deleteUser(id);
        return ResponseEntity.noContent().build();
    }

    @PostMapping("/users/{id}/roles")
    @PreAuthorize("hasAuthority('ADMIN_MANAGE_ROLES')")
    public ResponseEntity<UserResponse> assignRole(
            @PathVariable Long id,
            @Valid @RequestBody AssignRoleRequest request) {
        return ResponseEntity.ok(adminService.assignRole(id, request));
    }
}

Permission-Based Access Control

@Service
@RequiredArgsConstructor
public class DocumentService {

    @PreAuthorize("hasPermission(#documentId, 'Document', 'READ')")
    public Document getDocument(Long documentId) {
        return documentRepository.findById(documentId)
                .orElseThrow(() -> new DocumentNotFoundException(documentId));
    }

    @PreAuthorize("hasPermission(#documentId, 'Document', 'WRITE') or hasRole('ADMIN')")
    public Document updateDocument(Long documentId, UpdateDocumentRequest request) {
        Document document = getDocument(documentId);
        document.setContent(request.content());
        return documentRepository.save(document);
    }

    @PreAuthorize("@documentSecurityService.canAccess(#userEmail, #documentId)")
    public Document shareDocument(String userEmail, Long documentId) {
        // Implementation
    }
}

Custom Permission Evaluator

@Component
@RequiredArgsConstructor
public class DocumentPermissionEvaluator implements PermissionEvaluator {

    private final DocumentRepository documentRepository;

    @Override
    public boolean hasPermission(
            Authentication authentication,
            Object targetDomainObject,
            Object permission) {

        if (authentication == null || !(targetDomainObject instanceof Document)) {
            return false;
        }

        Document document = (Document) targetDomainObject;
        String username = authentication.getName();
        String requiredPermission = (String) permission;

        // Admin can do anything
        if (hasRole(authentication, "ADMIN")) {
            return true;
        }

        // Owner can read and write
        if (document.getOwner().getUsername().equals(username)) {
            return "READ".equals(requiredPermission) || "WRITE".equals(requiredPermission);
        }

        // Check shared permissions
        return document.getSharedWith().stream()
                .anyMatch(share -> share.getUser().getUsername().equals(username)
                        && share.getPermission().name().equals(requiredPermission));
    }

    @Override
    public boolean hasPermission(
            Authentication authentication,
            Serializable targetId,
            String targetType,
            Object permission) {

        if (!"Document".equals(targetType)) {
            return false;
        }

        Document document = documentRepository.findById((Long) targetId).orElse(null);
        return document != null && hasPermission(authentication, document, permission);
    }

    private boolean hasRole(Authentication authentication, String role) {
        return authentication.getAuthorities().stream()
                .anyMatch(auth -> auth.getAuthority().equals("ROLE_" + role));
    }
}

Database Entities

@Entity
@Table(name = "users")
@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(unique = true, nullable = false)
    private String username;

    @Column(unique = true, nullable = false)
    private String email;

    @Column(nullable = false)
    private String password;

    @Builder.Default
    @Enumerated(EnumType.STRING)
    private Role role = Role.USER;

    @Builder.Default
    private boolean enabled = true;

    @Builder.Default
    private boolean accountNonExpired = true;

    @Builder.Default
    private boolean accountNonLocked = true;

    @Builder.Default
    private boolean credentialsNonExpired = true;

    @OneToMany(mappedBy = "user", cascade = CascadeType.ALL, fetch = FetchType.LAZY)
    private Set<RefreshToken> refreshTokens = new HashSet<>();

    @CreationTimestamp
    @Column(name = "created_at", updatable = false)
    private LocalDateTime createdAt;

    @UpdateTimestamp
    @Column(name = "updated_at")
    private LocalDateTime updatedAt;
}

@Entity
@Table(name = "refresh_tokens")
@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
public class RefreshToken {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(nullable = false, unique = true)
    private String token;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "user_id", nullable = false)
    private User user;

    @Builder.Default
    private boolean revoked = false;

    @Builder.Default
    private boolean expired = false;

    @Column(name = "expiry_date")
    private LocalDateTime expiryDate;

    @CreationTimestamp
    @Column(name = "created_at", updatable = false)
    private LocalDateTime createdAt;
}

Testing JWT Security

@SpringBootTest
@AutoConfigureMockMvc
@TestPropertySource(properties = {
    "jwt.secret=test-secret-key-for-testing-only",
    "jwt.access-token-expiration=3600000"
})
class AuthenticationControllerTest {

    @Autowired
    private MockMvc mockMvc;

    @Autowired
    private ObjectMapper objectMapper;

    @Autowired
    private JwtService jwtService;

    @Test
    void shouldAuthenticateUser() throws Exception {
        AuthenticationRequest request = AuthenticationRequest.builder()
                .email("test@example.com")
                .password("password123")
                .build();

        mockMvc.perform(post("/api/v1/auth/authenticate")
                .contentType(MediaType.APPLICATION_JSON)
                .content(objectMapper.writeValueAsString(request)))
                .andExpect(status().isOk())
                .andExpect(jsonPath("$.accessToken").exists())
                .andExpect(jsonPath("$.refreshToken").exists())
                .andExpect(jsonPath("$.user.email").value("test@example.com"));
    }

    @Test
    void shouldDenyAccessWithoutToken() throws Exception {
        mockMvc.perform(get("/api/v1/admin/users"))
                .andExpect(status().isUnauthorized());
    }

    @Test
    @WithMockUser(roles = "ADMIN")
    void shouldAllowAdminAccess() throws Exception {
        mockMvc.perform(get("/api/v1/admin/users"))
                .andExpect(status().isOk());
    }

    @Test
    void shouldValidateJwtToken() throws Exception {
        UserDetails userDetails = User.withUsername("test@example.com")
                .password("password")
                .roles("USER")
                .build();

        String token = jwtService.generateAccessToken(userDetails);

        mockMvc.perform(get("/api/v1/auth/me")
                .header("Authorization", "Bearer " + token))
                .andExpect(status().isOk());
    }
}

Best Practices

1. Modern JWT Patterns

Key Rotation Strategy

@Component
@RequiredArgsConstructor
public class JwtKeyRotationService {

    private final SecretKeyRepository keyRepository;
    private final CacheManager cacheManager;

    @Scheduled(cron = "0 0 0 * * ?") // Daily at midnight
    public void rotateKeys() {
        SecretKey newKey = Keys.secretKeyFor(SignatureAlgorithm.HS256);
        keyRepository.save(new SecretKeyEntity(newKey, LocalDateTime.now()));
        cacheManager.getCache("jwt-keys").clear();
    }
}

Token Blacklisting

@Service
@RequiredArgsConstructor
public class TokenBlacklistService {

    private final RedisTemplate<string, string> redisTemplate;
    private static final String BLACKLIST_PREFIX = "blacklist:jwt:";

    public void blacklistToken(String token, long expirationTime) {
        String tokenId = extractTokenId(token);
        redisTemplate.opsForValue().set(
            BLACKLIST_PREFIX + tokenId,
            "1",
            expirationTime,
            TimeUnit.MILLISECONDS
        );
    }

    public boolean isBlacklisted(String token) {
        String tokenId = extractTokenId(token);
        return Boolean.TRUE.equals(redisTemplate.hasKey(BLACKLIST_PREFIX + tokenId));
    }
}

2. Security Configuration

• Always use HTTPS in production for JWT token transmission
• Set appropriate cookie flags: HttpOnly, Secure, SameSite
• Use strong secret keys: minimum 256 bits for HMAC algorithms
• Implement token expiration: Don't use tokens with infinite lifetime
• Validate all inputs: Never trust JWT claims without validation
• Implement key rotation: Regularly rotate signing keys
• Use token blacklisting: For logout and security incidents

2. Token Management

// Implement refresh token rotation
public class RefreshTokenService {

    @Transactional
    public String rotateRefreshToken(String oldToken) {
        RefreshToken refreshToken = refreshTokenRepository.findByToken(oldToken)
                .orElseThrow(() -> new RefreshTokenException("Invalid refresh token"));

        // Revoke old token
        refreshToken.setRevoked(true);
        refreshTokenRepository.save(refreshToken);

        // Generate new token
        return createRefreshToken(refreshToken.getUser().getUsername());
    }
}

3. Performance Optimization

// Cache user details to avoid database hits
@Service
@RequiredArgsConstructor
public class CachedUserDetailsService implements UserDetailsService {

    private final UserRepository userRepository;
    private final CacheManager cacheManager;

    @Override
    @Cacheable(value = "users", key = "#username")
    public UserDetails loadUserByUsername(String username) {
        User user = userRepository.findByEmail(username)
                .orElseThrow(() -> new UsernameNotFoundException(username));
        return new CustomUserDetails(user);
    }
}

4. Monitoring and Audit

@Component
@RequiredArgsConstructor
@Slf4j
public class SecurityAuditService {

    @EventListener
    public void handleAuthenticationSuccess(AuthenticationSuccessEvent event) {
        log.info("Authentication success for user: {}", event.getAuthentication().getName());
        // Store audit event
    }

    @EventListener
    public void handleAuthenticationFailure(AuthenticationFailureEvent event) {
        log.warn("Authentication failure for user: {}", event.getAuthentication().getName());
        // Store security event
    }

    @EventListener
    public void handleAuthorizationFailure(AuthorizationFailureEvent event) {
        log.warn("Authorization denied for user: {} on resource: {}",
                event.getAuthentication().getName(),
                event.getConfigAttributes());
    }
}

Constraints

1. Token Size Limitations

• JWT tokens should stay under HTTP header size limits (typically 8KB)
• Avoid storing large amounts of data in JWT claims
• Use references instead of embedding complete objects

2. Security Considerations

• Never store sensitive information in JWT tokens
• Implement proper token revocation strategies
• Use different keys for different environments (dev, staging, prod)
• Regularly rotate signing keys

3. Rate Limiting

@RestController
@RequestMapping("/api/v1/auth")
@RequiredArgsConstructor
public class AuthenticationController {

    @PostMapping("/authenticate")
    @RateLimiter(name = "auth", fallbackMethod = "authenticateFallback")
    public ResponseEntity<AuthenticationResponse> authenticate(@RequestBody AuthenticationRequest request) {
        // Implementation
    }

    public ResponseEntity<AuthenticationResponse> authenticateFallback(
            AuthenticationRequest request,
            CallNotPermittedException exception) {
        return ResponseEntity.status(HttpStatus.TOO_MANY_REQUESTS).build();
    }
}

4. CORS Configuration

@Configuration
public class CorsConfig {

    @Bean
    public CorsConfigurationSource corsConfigurationSource() {
        CorsConfiguration configuration = new CorsConfiguration();
        configuration.setAllowedOriginPatterns(List.of("*"));
        configuration.setAllowedMethods(List.of("GET", "POST", "PUT", "DELETE", "OPTIONS"));
        configuration.setAllowedHeaders(List.of("*"));
        configuration.setAllowCredentials(true);

        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        source.registerCorsConfiguration("/**", configuration);
        return source;
    }
}

Reference Materials

• Complete JWT Configuration Guide - Consolidated configuration patterns for Spring Security 6.x
• JWT Testing Guide - Comprehensive testing strategies
• JWT Quick Reference - Common patterns and quick examples
• Complete implementation examples
• Security hardening checklist
• Migration guide for Spring Security 6.x

Related Skills

• spring-boot-dependency-injection - Constructor injection patterns used throughout
• spring-boot-rest-api-standards - REST API security patterns and error handling
• unit-test-security-authorization - Testing Spring Security configurations
• spring-data-jpa - User entity and repository patterns
• spring-boot-actuator - Security monitoring and health endpoints