Polish "Replace anonymous class with lambdas"

See gh-17040

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/tomcat/TomcatServletWebServerFactoryTests.java

@@ -68,7 +68,6 @@ import org.mockito.InOrder;
 
 import org.springframework.boot.testsupport.rule.OutputCapture;
 import org.springframework.boot.web.server.WebServerException;
-import org.springframework.boot.web.servlet.ServletContextInitializer;
 import org.springframework.boot.web.servlet.server.AbstractServletWebServerFactory;
 import org.springframework.boot.web.servlet.server.AbstractServletWebServerFactoryTests;
 import org.springframework.core.io.ByteArrayResource;
@@ -538,13 +537,12 @@ public class TomcatServletWebServerFactoryTests
 			throws IOException, URISyntaxException {
 		TomcatServletWebServerFactory factory = new TomcatServletWebServerFactory(0);
 		AtomicReference<ServletContext> servletContextReference = new AtomicReference<>();
-		factory.addInitializers((ServletContextInitializer) servletContext -> {
+		factory.addInitializers((servletContext) -> {
 			servletContextReference.set(servletContext);
 			Dynamic servlet = servletContext.addServlet("upload", new HttpServlet() {
 
 				@Override
-				protected void doPost(HttpServletRequest req,
-						HttpServletResponse resp)
+				protected void doPost(HttpServletRequest req, HttpServletResponse resp)
 						throws ServletException, IOException {
 					req.getParts();
 				}

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/servlet/server/AbstractServletWebServerFactoryTests.java

@@ -25,7 +25,6 @@ import java.io.PrintWriter;
 import java.net.InetSocketAddress;
 import java.net.MalformedURLException;
 import java.net.ServerSocket;
-import java.net.Socket;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.net.URL;
@@ -75,8 +74,6 @@ import org.apache.http.conn.ssl.TrustSelfSignedStrategy;
 import org.apache.http.impl.client.HttpClientBuilder;
 import org.apache.http.impl.client.HttpClients;
 import org.apache.http.protocol.HttpContext;
-import org.apache.http.ssl.PrivateKeyDetails;
-import org.apache.http.ssl.PrivateKeyStrategy;
 import org.apache.http.ssl.SSLContextBuilder;
 import org.apache.http.ssl.TrustStrategy;
 import org.apache.jasper.EmbeddedServletOptions;