Clean up warnings in spring-webmvc

spring-webmvc/src/main/java/org/springframework/web/servlet/config/AnnotationDrivenBeanDefinitionParser.java

@@ -449,7 +449,6 @@ class AnnotationDrivenBeanDefinitionParser implements BeanDefinitionParser {
 		return null;
 	}
 
-	@SuppressWarnings("deprecation")
 	private ManagedList<?> getMessageConverters(Element element, Object source, ParserContext parserContext) {
 		Element convertersElement = DomUtils.getChildElementByTagName(element, "message-converters");
 		ManagedList<? super Object> messageConverters = new ManagedList<Object>();

spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/WebMvcConfigurationSupport.java

@@ -538,7 +538,6 @@ public class WebMvcConfigurationSupport implements ApplicationContextAware, Serv
 	 * Subclasses can call this method from {@link #configureMessageConverters(List)}.
 	 * @param messageConverters the list to add the default message converters to
 	 */
-	@SuppressWarnings("deprecation")
 	protected final void addDefaultHttpMessageConverters(List<HttpMessageConverter<?>> messageConverters) {
 		StringHttpMessageConverter stringConverter = new StringHttpMessageConverter();
 		stringConverter.setWriteAcceptCharset(false);

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/HttpHeadersReturnValueHandler.java

@@ -40,6 +40,7 @@ public class HttpHeadersReturnValueHandler implements HandlerMethodReturnValueHa
 	}
 
 	@Override
+	@SuppressWarnings("resource")
 	public void handleReturnValue(Object returnValue, MethodParameter returnType,
 			ModelAndViewContainer mavContainer, NativeWebRequest webRequest) throws Exception {
 
@@ -55,4 +56,5 @@ public class HttpHeadersReturnValueHandler implements HandlerMethodReturnValueHa
 			outputMessage.getBody(); // flush headers
 		}
 	}
+
 }

spring-webmvc/src/main/java/org/springframework/web/servlet/support/AbstractDispatcherServletInitializer.java

@@ -30,7 +30,6 @@ import org.springframework.util.Assert;
 import org.springframework.util.ObjectUtils;
 import org.springframework.web.context.AbstractContextLoaderInitializer;
 import org.springframework.web.context.WebApplicationContext;
-import org.springframework.web.filter.DelegatingFilterProxy;
 import org.springframework.web.servlet.DispatcherServlet;
 
 /**