Simplify authorization server filter chain in samples

Closes gh-707

samples/custom-consent-authorizationserver/src/main/java/sample/config/AuthorizationServerConfig.java

@@ -27,7 +27,6 @@ import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.Ordered;
 import org.springframework.core.annotation.Order;
-import org.springframework.security.config.Customizer;
 import org.springframework.security.config.annotation.web.builders.HttpSecurity;
 import org.springframework.security.config.annotation.web.configurers.oauth2.server.authorization.OAuth2AuthorizationServerConfigurer;
 import org.springframework.security.oauth2.core.AuthorizationGrantType;
@@ -41,6 +40,7 @@ import org.springframework.security.oauth2.server.authorization.client.Registere
 import org.springframework.security.oauth2.server.authorization.config.ClientSettings;
 import org.springframework.security.oauth2.server.authorization.config.ProviderSettings;
 import org.springframework.security.web.SecurityFilterChain;
+import org.springframework.security.web.authentication.LoginUrlAuthenticationEntryPoint;
 import org.springframework.security.web.util.matcher.RequestMatcher;
 
 /**
@@ -69,8 +69,11 @@ public class AuthorizationServerConfig {
 				authorizeRequests.anyRequest().authenticated()
 			)
 			.csrf(csrf -> csrf.ignoringRequestMatchers(endpointsMatcher))
+			.exceptionHandling(exceptions ->
+				exceptions.authenticationEntryPoint(new LoginUrlAuthenticationEntryPoint("/login"))
+			)
 			.apply(authorizationServerConfigurer);
-		return http.formLogin(Customizer.withDefaults()).build();
+		return http.build();
 	}
 
 	// @formatter:off

samples/default-authorizationserver/src/main/java/sample/config/AuthorizationServerConfig.java

@@ -31,7 +31,6 @@ import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.jdbc.datasource.embedded.EmbeddedDatabase;
 import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseBuilder;
 import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseType;
-import org.springframework.security.config.Customizer;
 import org.springframework.security.config.annotation.web.builders.HttpSecurity;
 import org.springframework.security.config.annotation.web.configuration.OAuth2AuthorizationServerConfiguration;
 import org.springframework.security.oauth2.core.AuthorizationGrantType;
@@ -47,6 +46,7 @@ import org.springframework.security.oauth2.server.authorization.client.Registere
 import org.springframework.security.oauth2.server.authorization.config.ClientSettings;
 import org.springframework.security.oauth2.server.authorization.config.ProviderSettings;
 import org.springframework.security.web.SecurityFilterChain;
+import org.springframework.security.web.authentication.LoginUrlAuthenticationEntryPoint;
 
 /**
  * @author Joe Grandja
@@ -59,7 +59,13 @@ public class AuthorizationServerConfig {
 	@Order(Ordered.HIGHEST_PRECEDENCE)
 	public SecurityFilterChain authorizationServerSecurityFilterChain(HttpSecurity http) throws Exception {
 		OAuth2AuthorizationServerConfiguration.applyDefaultSecurity(http);
-		return http.formLogin(Customizer.withDefaults()).build();
+		// @formatter:off
+		http
+			.exceptionHandling(exceptions ->
+				exceptions.authenticationEntryPoint(new LoginUrlAuthenticationEntryPoint("/login"))
+			);
+		// @formatter:on
+		return http.build();
 	}
 
 	// @formatter:off

samples/federated-identity-authorizationserver/src/main/java/sample/config/AuthorizationServerConfig.java

@@ -33,7 +33,6 @@ import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.jdbc.datasource.embedded.EmbeddedDatabase;
 import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseBuilder;
 import org.springframework.jdbc.datasource.embedded.EmbeddedDatabaseType;
-import org.springframework.security.config.Customizer;
 import org.springframework.security.config.annotation.web.builders.HttpSecurity;
 import org.springframework.security.config.annotation.web.configuration.OAuth2AuthorizationServerConfiguration;
 import org.springframework.security.oauth2.core.AuthorizationGrantType;
@@ -64,7 +63,7 @@ public class AuthorizationServerConfig {
 	public SecurityFilterChain authorizationServerSecurityFilterChain(HttpSecurity http) throws Exception {
 		OAuth2AuthorizationServerConfiguration.applyDefaultSecurity(http);
 		http.apply(new FederatedIdentityConfigurer());
-		return http.formLogin(Customizer.withDefaults()).build();
+		return http.build();
 	}
 
 	@Bean