Make AuthenticationProvider implementations final

Closes gh-360

oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/authentication/OAuth2AuthorizationCodeAuthenticationProvider.java

@@ -69,7 +69,7 @@ import static org.springframework.security.oauth2.server.authorization.authentic
  * @see <a target="_blank" href="https://tools.ietf.org/html/rfc6749#section-4.1">Section 4.1 Authorization Code Grant</a>
  * @see <a target="_blank" href="https://tools.ietf.org/html/rfc6749#section-4.1.3">Section 4.1.3 Access Token Request</a>
  */
-public class OAuth2AuthorizationCodeAuthenticationProvider implements AuthenticationProvider {
+public final class OAuth2AuthorizationCodeAuthenticationProvider implements AuthenticationProvider {
 	private static final OAuth2TokenType AUTHORIZATION_CODE_TOKEN_TYPE =
 			new OAuth2TokenType(OAuth2ParameterNames.CODE);
 	private static final OAuth2TokenType ID_TOKEN_TOKEN_TYPE =
@@ -92,7 +92,7 @@ public class OAuth2AuthorizationCodeAuthenticationProvider implements Authentica
 		this.jwtEncoder = jwtEncoder;
 	}
 
-	public final void setJwtCustomizer(OAuth2TokenCustomizer<JwtEncodingContext> jwtCustomizer) {
+	public void setJwtCustomizer(OAuth2TokenCustomizer<JwtEncodingContext> jwtCustomizer) {
 		Assert.notNull(jwtCustomizer, "jwtCustomizer cannot be null");
 		this.jwtCustomizer = jwtCustomizer;
 	}

oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/authentication/OAuth2AuthorizationCodeRequestAuthenticationProvider.java

@@ -63,7 +63,7 @@ import org.springframework.web.util.UriComponentsBuilder;
  * @see OAuth2AuthorizationConsentService
  * @see <a target="_blank" href="https://datatracker.ietf.org/doc/html/rfc6749#section-4.1.1">Section 4.1.1 Authorization Request</a>
  */
-public class OAuth2AuthorizationCodeRequestAuthenticationProvider implements AuthenticationProvider {
+public final class OAuth2AuthorizationCodeRequestAuthenticationProvider implements AuthenticationProvider {
 	private static final OAuth2TokenType STATE_TOKEN_TYPE = new OAuth2TokenType(OAuth2ParameterNames.STATE);
 	private static final String PKCE_ERROR_URI = "https://datatracker.ietf.org/doc/html/rfc7636#section-4.4.1";
 	private static final Pattern LOOPBACK_ADDRESS_PATTERN =

oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/authentication/OAuth2ClientAuthenticationProvider.java

@@ -55,7 +55,7 @@ import org.springframework.util.StringUtils;
  * @see OAuth2AuthorizationService
  * @see PasswordEncoder
  */
-public class OAuth2ClientAuthenticationProvider implements AuthenticationProvider {
+public final class OAuth2ClientAuthenticationProvider implements AuthenticationProvider {
 	private static final OAuth2TokenType AUTHORIZATION_CODE_TOKEN_TYPE = new OAuth2TokenType(OAuth2ParameterNames.CODE);
 	private final RegisteredClientRepository registeredClientRepository;
 	private final OAuth2AuthorizationService authorizationService;
@@ -84,7 +84,7 @@ public class OAuth2ClientAuthenticationProvider implements AuthenticationProvide
 	 *
 	 * @param passwordEncoder the {@link PasswordEncoder} used to validate the client secret
 	 */
-	public final void setPasswordEncoder(PasswordEncoder passwordEncoder) {
+	public void setPasswordEncoder(PasswordEncoder passwordEncoder) {
 		Assert.notNull(passwordEncoder, "passwordEncoder cannot be null");
 		this.passwordEncoder = passwordEncoder;
 	}

oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/authentication/OAuth2ClientCredentialsAuthenticationProvider.java

@@ -59,7 +59,7 @@ import static org.springframework.security.oauth2.server.authorization.authentic
  * @see <a target="_blank" href="https://tools.ietf.org/html/rfc6749#section-4.4">Section 4.4 Client Credentials Grant</a>
  * @see <a target="_blank" href="https://tools.ietf.org/html/rfc6749#section-4.4.2">Section 4.4.2 Access Token Request</a>
  */
-public class OAuth2ClientCredentialsAuthenticationProvider implements AuthenticationProvider {
+public final class OAuth2ClientCredentialsAuthenticationProvider implements AuthenticationProvider {
 	private final OAuth2AuthorizationService authorizationService;
 	private final JwtEncoder jwtEncoder;
 	private OAuth2TokenCustomizer<JwtEncodingContext> jwtCustomizer = (context) -> {};
@@ -79,7 +79,7 @@ public class OAuth2ClientCredentialsAuthenticationProvider implements Authentica
 		this.jwtEncoder = jwtEncoder;
 	}
 
-	public final void setJwtCustomizer(OAuth2TokenCustomizer<JwtEncodingContext> jwtCustomizer) {
+	public void setJwtCustomizer(OAuth2TokenCustomizer<JwtEncodingContext> jwtCustomizer) {
 		Assert.notNull(jwtCustomizer, "jwtCustomizer cannot be null");
 		this.jwtCustomizer = jwtCustomizer;
 	}

oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/authentication/OAuth2RefreshTokenAuthenticationProvider.java

@@ -72,7 +72,7 @@ import static org.springframework.security.oauth2.server.authorization.authentic
  * @see <a target="_blank" href="https://tools.ietf.org/html/rfc6749#section-1.5">Section 1.5 Refresh Token Grant</a>
  * @see <a target="_blank" href="https://tools.ietf.org/html/rfc6749#section-6">Section 6 Refreshing an Access Token</a>
  */
-public class OAuth2RefreshTokenAuthenticationProvider implements AuthenticationProvider {
+public final class OAuth2RefreshTokenAuthenticationProvider implements AuthenticationProvider {
 	private static final OAuth2TokenType ID_TOKEN_TOKEN_TYPE = new OAuth2TokenType(OidcParameterNames.ID_TOKEN);
 	private static final StringKeyGenerator TOKEN_GENERATOR = new Base64StringKeyGenerator(Base64.getUrlEncoder().withoutPadding(), 96);
 	private final OAuth2AuthorizationService authorizationService;
@@ -94,7 +94,7 @@ public class OAuth2RefreshTokenAuthenticationProvider implements AuthenticationP
 		this.jwtEncoder = jwtEncoder;
 	}
 
-	public final void setJwtCustomizer(OAuth2TokenCustomizer<JwtEncodingContext> jwtCustomizer) {
+	public void setJwtCustomizer(OAuth2TokenCustomizer<JwtEncodingContext> jwtCustomizer) {
 		Assert.notNull(jwtCustomizer, "jwtCustomizer cannot be null");
 		this.jwtCustomizer = jwtCustomizer;
 	}

oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/authentication/OAuth2TokenIntrospectionAuthenticationProvider.java

@@ -47,7 +47,7 @@ import static org.springframework.security.oauth2.server.authorization.authentic
  * @see OAuth2AuthorizationService
  * @see <a target="_blank" href="https://tools.ietf.org/html/rfc7662#section-2.1">Section 2.1 Introspection Request</a>
  */
-public class OAuth2TokenIntrospectionAuthenticationProvider implements AuthenticationProvider {
+public final class OAuth2TokenIntrospectionAuthenticationProvider implements AuthenticationProvider {
 	private final RegisteredClientRepository registeredClientRepository;
 	private final OAuth2AuthorizationService authorizationService;
 

oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/authentication/OAuth2TokenRevocationAuthenticationProvider.java

@@ -39,7 +39,7 @@ import static org.springframework.security.oauth2.server.authorization.authentic
  * @see OAuth2AuthorizationService
  * @see <a target="_blank" href="https://tools.ietf.org/html/rfc7009#section-2.1">Section 2.1 Revocation Request</a>
  */
-public class OAuth2TokenRevocationAuthenticationProvider implements AuthenticationProvider {
+public final class OAuth2TokenRevocationAuthenticationProvider implements AuthenticationProvider {
 	private final OAuth2AuthorizationService authorizationService;
 
 	/**

oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/oidc/authentication/OidcClientRegistrationAuthenticationProvider.java

@@ -54,7 +54,7 @@ import org.springframework.util.CollectionUtils;
  * @see OAuth2AuthorizationService
  * @see <a href="https://openid.net/specs/openid-connect-registration-1_0.html#ClientRegistration">3. Client Registration Endpoint</a>
  */
-public class OidcClientRegistrationAuthenticationProvider implements AuthenticationProvider {
+public final class OidcClientRegistrationAuthenticationProvider implements AuthenticationProvider {
 	private static final StringKeyGenerator CLIENT_ID_GENERATOR = new Base64StringKeyGenerator(
 			Base64.getUrlEncoder().withoutPadding(), 32);
 	private static final StringKeyGenerator CLIENT_SECRET_GENERATOR = new Base64StringKeyGenerator(