Remove unused imports

This commit also adds UnusedImportsCheck Checkstyle module.

web/src/main/java/org/springframework/security/web/authentication/session/SessionFixationProtectionStrategy.java

@@ -18,7 +18,6 @@ package org.springframework.security.web.authentication.session;
 
 import java.util.Enumeration;
 import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
 
 import javax.servlet.http.HttpServletRequest;

web/src/main/java/org/springframework/security/web/server/ServerHttpBasicAuthenticationConverter.java

@@ -18,7 +18,6 @@ package org.springframework.security.web.server;
 import java.util.Base64;
 import java.util.function.Function;
 
-import org.springframework.core.convert.converter.Converter;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.server.reactive.ServerHttpRequest;
 import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;

web/src/main/java/org/springframework/security/web/server/WebFilterChainProxy.java

@@ -15,11 +15,9 @@
  */
 package org.springframework.security.web.server;
 
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
-import org.springframework.security.web.server.util.matcher.ServerWebExchangeMatchers;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.WebFilter;
 import org.springframework.web.server.WebFilterChain;

web/src/main/java/org/springframework/security/web/server/authentication/RedirectServerAuthenticationFailureHandler.java

@@ -18,13 +18,9 @@ package org.springframework.security.web.server.authentication;
 
 import org.springframework.security.core.AuthenticationException;
 import org.springframework.security.web.server.DefaultServerRedirectStrategy;
-import org.springframework.security.web.server.ServerAuthenticationEntryPoint;
 import org.springframework.security.web.server.ServerRedirectStrategy;
 import org.springframework.security.web.server.WebFilterExchange;
-import org.springframework.security.web.server.savedrequest.ServerRequestCache;
-import org.springframework.security.web.server.savedrequest.WebSessionServerRequestCache;
 import org.springframework.util.Assert;
-import org.springframework.web.server.ServerWebExchange;
 import reactor.core.publisher.Mono;
 
 import java.net.URI;

web/src/main/java/org/springframework/security/web/server/authentication/ServerAuthenticationFailureHandler.java

@@ -19,7 +19,6 @@ package org.springframework.security.web.server.authentication;
 import org.springframework.security.core.AuthenticationException;
 import reactor.core.publisher.Mono;
 
-import org.springframework.security.core.Authentication;
 import org.springframework.security.web.server.WebFilterExchange;
 
 /**

web/src/main/java/org/springframework/security/web/server/authentication/logout/SecurityContextServerLogoutHandler.java

@@ -17,16 +17,12 @@
 package org.springframework.security.web.server.authentication.logout;
 
 import org.springframework.security.core.Authentication;
-import org.springframework.security.web.server.DefaultServerRedirectStrategy;
-import org.springframework.security.web.server.ServerRedirectStrategy;
 import org.springframework.security.web.server.context.ServerSecurityContextRepository;
 import org.springframework.security.web.server.WebFilterExchange;
 import org.springframework.security.web.server.context.WebSessionServerSecurityContextRepository;
 import org.springframework.util.Assert;
 import reactor.core.publisher.Mono;
 
-import java.net.URI;
-
 /**
  * A {@link ServerLogoutHandler} which removes the SecurityContext using the provided
  * {@link ServerSecurityContextRepository}

web/src/main/java/org/springframework/security/web/server/authorization/AuthorizationWebFilter.java

@@ -19,7 +19,6 @@ package org.springframework.security.web.server.authorization;
 import org.springframework.security.authorization.ReactiveAuthorizationManager;
 import org.springframework.security.core.context.ReactiveSecurityContextHolder;
 import org.springframework.security.core.context.SecurityContext;
-import org.springframework.security.core.context.SecurityContextImpl;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.WebFilter;
 import org.springframework.web.server.WebFilterChain;

web/src/main/java/org/springframework/security/web/server/authorization/HttpStatusServerAccessDeniedHandler.java

@@ -20,7 +20,6 @@ import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DataBufferFactory;
 import org.springframework.core.io.buffer.DataBufferUtils;
 import org.springframework.http.MediaType;
-import org.springframework.http.server.reactive.ServerHttpResponse;
 import reactor.core.publisher.Mono;
 
 import org.springframework.http.HttpStatus;

web/src/main/java/org/springframework/security/web/server/authorization/ServerAccessDeniedHandler.java

@@ -16,7 +16,6 @@
 package org.springframework.security.web.server.authorization;
 
 import org.springframework.security.access.AccessDeniedException;
-import org.springframework.security.core.AuthenticationException;
 import org.springframework.web.server.ServerWebExchange;
 import reactor.core.publisher.Mono;
 

web/src/main/java/org/springframework/security/web/server/context/SecurityContextServerWebExchange.java

@@ -17,7 +17,6 @@ package org.springframework.security.web.server.context;
 
 import java.security.Principal;
 
-import org.springframework.security.core.Authentication;
 import org.springframework.security.core.context.SecurityContext;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.ServerWebExchangeDecorator;

web/src/main/java/org/springframework/security/web/server/context/SecurityContextServerWebExchangeWebFilter.java

@@ -16,9 +16,7 @@
 
 package org.springframework.security.web.server.context;
 
-import org.springframework.security.core.Authentication;
 import org.springframework.security.core.context.ReactiveSecurityContextHolder;
-import org.springframework.security.core.context.SecurityContextImpl;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.WebFilter;
 import org.springframework.web.server.WebFilterChain;

web/src/main/java/org/springframework/security/web/server/savedrequest/WebSessionServerRequestCache.java

@@ -27,8 +27,6 @@ import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.WebSession;
 import reactor.core.publisher.Mono;
 
-import java.net.URI;
-
 /**
  * An implementation of {@link ServerRequestCache} that saves the
  * {@link ServerHttpRequest} in the {@link WebSession}.

web/src/main/java/org/springframework/security/web/server/ui/LoginPageGeneratingWebFilter.java

@@ -18,7 +18,6 @@ package org.springframework.security.web.server.ui;
 
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DataBufferFactory;
-import org.springframework.core.io.buffer.DataBufferUtils;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;

web/src/main/java/org/springframework/security/web/server/ui/LogoutPageGeneratingWebFilter.java

@@ -25,7 +25,6 @@ import org.springframework.http.server.reactive.ServerHttpResponse;
 import org.springframework.security.web.server.csrf.CsrfToken;
 import org.springframework.security.web.server.util.matcher.ServerWebExchangeMatcher;
 import org.springframework.security.web.server.util.matcher.ServerWebExchangeMatchers;
-import org.springframework.util.MultiValueMap;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.WebFilter;
 import org.springframework.web.server.WebFilterChain;

web/src/main/java/org/springframework/security/web/server/util/matcher/OrServerWebExchangeMatcher.java

@@ -17,7 +17,6 @@ package org.springframework.security.web.server.util.matcher;
 
 import java.util.Arrays;
 import java.util.List;
-import java.util.function.Predicate;
 
 import org.springframework.util.Assert;
 import org.springframework.web.server.ServerWebExchange;