Nullability fine-tuning around declaration inconsistencies

Issue: SPR-15720
Issue: SPR-15792

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

@@ -72,9 +72,8 @@ public interface AsyncHandlerInterceptor extends HandlerInterceptor {
 	 * execution, for type and/or instance examination
 	 * @throws Exception in case of errors
 	 */
-	default void afterConcurrentHandlingStarted(
-			HttpServletRequest request, HttpServletResponse response, Object handler)
-			throws Exception {
+	default void afterConcurrentHandlingStarted(HttpServletRequest request, HttpServletResponse response,
+			Object handler) throws Exception {
 	}
 
 }

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

@@ -120,9 +120,8 @@ public interface HandlerInterceptor {
 	 * (can also be {@code null})
 	 * @throws Exception in case of errors
 	 */
-	default void postHandle(
-			HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView)
-			throws Exception {
+	default void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
+			@Nullable ModelAndView modelAndView) throws Exception {
 	}
 
 	/**
@@ -145,9 +144,8 @@ public interface HandlerInterceptor {
 	 * @param ex exception thrown on handler execution, if any
 	 * @throws Exception in case of errors
 	 */
-	default void afterCompletion(
-			HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable Exception ex)
-			throws Exception {
+	default void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,
+			@Nullable Exception ex) throws Exception {
 	}
 
 }

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

@@ -681,10 +681,13 @@ class AnnotationDrivenBeanDefinitionParser implements BeanDefinitionParser {
 	static class CompositeUriComponentsContributorFactoryBean
 			implements FactoryBean<CompositeUriComponentsContributor>, InitializingBean {
 
+		@Nullable
 		private RequestMappingHandlerAdapter handlerAdapter;
 
+		@Nullable
 		private ConversionService conversionService;
 
+		@Nullable
 		private CompositeUriComponentsContributor uriComponentsContributor;
 
 		public void setHandlerAdapter(RequestMappingHandlerAdapter handlerAdapter) {
@@ -697,6 +700,7 @@ class AnnotationDrivenBeanDefinitionParser implements BeanDefinitionParser {
 
 		@Override
 		public void afterPropertiesSet() {
+			Assert.state(this.handlerAdapter != null, "No RequestMappingHandlerAdapter set");
 			this.uriComponentsContributor = new CompositeUriComponentsContributor(
 					this.handlerAdapter.getArgumentResolvers(), this.conversionService);
 		}

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

@@ -37,8 +37,10 @@ import org.springframework.web.context.request.async.WebAsyncTask;
  */
 public class AsyncSupportConfigurer {
 
+	@Nullable
 	private AsyncTaskExecutor taskExecutor;
 
+	@Nullable
 	private Long timeout;
 
 	private final List<CallableProcessingInterceptor> callableInterceptors = new ArrayList<>();

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

@@ -39,14 +39,19 @@ import org.springframework.web.util.pattern.ParsingPathMatcher;
  */
 public class PathMatchConfigurer {
 
+	@Nullable
 	private Boolean suffixPatternMatch;
 
+	@Nullable
 	private Boolean trailingSlashMatch;
 
+	@Nullable
 	private Boolean registeredSuffixPatternMatch;
 
+	@Nullable
 	private UrlPathHelper urlPathHelper;
 
+	@Nullable
 	private PathMatcher pathMatcher;
 
 
@@ -131,7 +136,8 @@ public class PathMatchConfigurer {
 
 	@Nullable
 	public PathMatcher getPathMatcher() {
-		if (this.pathMatcher instanceof ParsingPathMatcher && (this.trailingSlashMatch || this.suffixPatternMatch)) {
+		if (this.pathMatcher instanceof ParsingPathMatcher &&
+				(Boolean.TRUE.equals(this.trailingSlashMatch) || Boolean.TRUE.equals(this.suffixPatternMatch))) {
 			throw new IllegalStateException("When using a ParsingPathMatcher, useTrailingSlashMatch" +
 					" and useSuffixPatternMatch should be set to 'false'.");
 		}

spring-webmvc/src/main/java/org/springframework/web/servlet/handler/HandlerInterceptorAdapter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -46,27 +46,24 @@ public abstract class HandlerInterceptorAdapter implements AsyncHandlerIntercept
 	 * This implementation is empty.
 	 */
 	@Override
-	public void postHandle(
-			HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView)
-			throws Exception {
+	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
+			@Nullable ModelAndView modelAndView) throws Exception {
 	}
 
 	/**
 	 * This implementation is empty.
 	 */
 	@Override
-	public void afterCompletion(
-			HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
-			throws Exception {
+	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,
+			@Nullable Exception ex) throws Exception {
 	}
 
 	/**
 	 * This implementation is empty.
 	 */
 	@Override
-	public void afterConcurrentHandlingStarted(
-			HttpServletRequest request, HttpServletResponse response, Object handler)
-			throws Exception {
+	public void afterConcurrentHandlingStarted(HttpServletRequest request, HttpServletResponse response,
+			Object handler) throws Exception {
 	}
 
 }

spring-webmvc/src/main/java/org/springframework/web/servlet/handler/MappedInterceptor.java

@@ -136,26 +136,6 @@ public final class MappedInterceptor implements HandlerInterceptor {
 		return this.interceptor;
 	}
 
-	@Override
-	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
-		return this.interceptor.preHandle(request, response, handler);
-	}
-
-	@Override
-	public void postHandle(
-			HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView)
-			throws Exception {
-
-		this.interceptor.postHandle(request, response, handler, modelAndView);
-	}
-
-	@Override
-	public void afterCompletion(
-			HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable Exception ex)
-			throws Exception {
-
-		this.interceptor.afterCompletion(request, response, handler, ex);
-	}
 
 	/**
 	 * Returns {@code true} if the interceptor applies to the given request path.
@@ -183,4 +163,26 @@ public final class MappedInterceptor implements HandlerInterceptor {
 			return false;
 		}
 	}
+
+	@Override
+	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
+			throws Exception {
+
+		return this.interceptor.preHandle(request, response, handler);
+	}
+
+	@Override
+	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
+			@Nullable ModelAndView modelAndView) throws Exception {
+
+		this.interceptor.postHandle(request, response, handler, modelAndView);
+	}
+
+	@Override
+	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,
+			@Nullable Exception ex) throws Exception {
+
+		this.interceptor.afterCompletion(request, response, handler, ex);
+	}
+
 }

spring-webmvc/src/main/java/org/springframework/web/servlet/handler/WebRequestHandlerInterceptorAdapter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -59,16 +59,16 @@ public class WebRequestHandlerInterceptorAdapter implements AsyncHandlerIntercep
 	}
 
 	@Override
-	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView)
-			throws Exception {
+	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
+			@Nullable ModelAndView modelAndView) throws Exception {
 
 		this.requestInterceptor.postHandle(new DispatcherServletWebRequest(request, response),
 				(modelAndView != null && !modelAndView.wasCleared() ? modelAndView.getModelMap() : null));
 	}
 
 	@Override
-	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
-			throws Exception {
+	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,
+			@Nullable Exception ex) throws Exception {
 
 		this.requestInterceptor.afterCompletion(new DispatcherServletWebRequest(request, response), ex);
 	}

spring-webmvc/src/main/java/org/springframework/web/servlet/i18n/AbstractLocaleContextResolver.java

@@ -66,7 +66,7 @@ public abstract class AbstractLocaleContextResolver extends AbstractLocaleResolv
 	}
 
 	@Override
-	public void setLocale(HttpServletRequest request, HttpServletResponse response, @Nullable Locale locale) {
+	public void setLocale(HttpServletRequest request, @Nullable HttpServletResponse response, @Nullable Locale locale) {
 		setLocaleContext(request, response, (locale != null ? new SimpleLocaleContext(locale) : null));
 	}
 

spring-webmvc/src/main/java/org/springframework/web/servlet/i18n/AcceptHeaderLocaleResolver.java

@@ -127,7 +127,7 @@ public class AcceptHeaderLocaleResolver implements LocaleResolver {
 	}
 
 	@Override
-	public void setLocale(HttpServletRequest request, HttpServletResponse response, @Nullable Locale locale) {
+	public void setLocale(HttpServletRequest request, @Nullable HttpServletResponse response, @Nullable Locale locale) {
 		throw new UnsupportedOperationException(
 				"Cannot change HTTP accept header - use a different locale resolution strategy");
 	}

spring-webmvc/src/main/java/org/springframework/web/servlet/i18n/LocaleChangeInterceptor.java

@@ -52,6 +52,7 @@ public class LocaleChangeInterceptor extends HandlerInterceptorAdapter {
 
 	private String paramName = DEFAULT_PARAM_NAME;
 
+	@Nullable
 	private String[] httpMethods;
 
 	private boolean ignoreInvalidLocale = false;
@@ -80,7 +81,7 @@ public class LocaleChangeInterceptor extends HandlerInterceptorAdapter {
 	 * @param httpMethods the methods
 	 * @since 4.2
 	 */
-	public void setHttpMethods(String... httpMethods) {
+	public void setHttpMethods(@Nullable String... httpMethods) {
 		this.httpMethods = httpMethods;
 	}
 
@@ -88,6 +89,7 @@ public class LocaleChangeInterceptor extends HandlerInterceptorAdapter {
 	 * Return the configured HTTP methods.
 	 * @since 4.2
 	 */
+	@Nullable
 	public String[] getHttpMethods() {
 		return this.httpMethods;
 	}
@@ -112,8 +114,6 @@ public class LocaleChangeInterceptor extends HandlerInterceptorAdapter {
 	 * Specify whether to parse request parameter values as BCP 47 language tags
 	 * instead of Java's legacy locale specification format.
 	 * The default is {@code false}.
-	 * <p>Note: This mode requires JDK 7 or higher. Set this flag to {@code true}
-	 * for BCP 47 compliance on JDK 7+ only.
 	 * @since 4.3
 	 * @see Locale#forLanguageTag(String)
 	 * @see Locale#toLanguageTag()

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/WebContentInterceptor.java

@@ -20,7 +20,6 @@ import java.util.Enumeration;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Properties;
-
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
@@ -254,18 +253,16 @@ public class WebContentInterceptor extends WebContentGenerator implements Handle
 	 * This implementation is empty.
 	 */
 	@Override
-	public void postHandle(
-			HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView)
-			throws Exception {
+	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
+			@Nullable ModelAndView modelAndView) throws Exception {
 	}
 
 	/**
 	 * This implementation is empty.
 	 */
 	@Override
-	public void afterCompletion(
-			HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
-			throws Exception {
+	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,
+			@Nullable Exception ex) throws Exception {
 	}
 
 }

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/AbstractNameValueExpression.java

@@ -60,6 +60,7 @@ abstract class AbstractNameValueExpression<T> implements NameValueExpression<T>
 	}
 
 	@Override
+	@Nullable
 	public T getValue() {
 		return this.value;
 	}

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

@@ -79,7 +79,7 @@ public class DeferredResultMethodReturnValueHandler implements HandlerMethodRetu
 		DeferredResult<Object> result = new DeferredResult<>();
 		future.addCallback(new ListenableFutureCallback<Object>() {
 			@Override
-			public void onSuccess(Object value) {
+			public void onSuccess(@Nullable Object value) {
 				result.setResult(value);
 			}
 			@Override

spring-webmvc/src/main/java/org/springframework/web/servlet/resource/DefaultServletHttpRequestHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,6 +23,8 @@ import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 import org.springframework.web.HttpRequestHandler;
 import org.springframework.web.context.ServletContextAware;
@@ -66,8 +68,10 @@ public class DefaultServletHttpRequestHandler implements HttpRequestHandler, Ser
 	private static final String WEBSPHERE_DEFAULT_SERVLET_NAME = "SimpleFileServlet";
 
 
+	@Nullable
 	private String defaultServletName;
 
+	@Nullable
 	private ServletContext servletContext;
 
 
@@ -114,6 +118,7 @@ public class DefaultServletHttpRequestHandler implements HttpRequestHandler, Ser
 	public void handleRequest(HttpServletRequest request, HttpServletResponse response)
 			throws ServletException, IOException {
 
+		Assert.state(this.servletContext != null, "No ServletContext set");
 		RequestDispatcher rd = this.servletContext.getNamedDispatcher(this.defaultServletName);
 		if (rd == null) {
 			throw new IllegalStateException("A RequestDispatcher could not be located for the default servlet '" +

spring-webmvc/src/main/java/org/springframework/web/servlet/resource/TransformedResource.java

@@ -53,6 +53,7 @@ public class TransformedResource extends ByteArrayResource {
 
 
 	@Override
+	@Nullable
 	public String getFilename() {
 		return this.filename;
 	}

spring-webmvc/src/main/java/org/springframework/web/servlet/tags/EscapeBodyTag.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,6 +21,8 @@ import javax.servlet.jsp.JspException;
 import javax.servlet.jsp.tagext.BodyContent;
 import javax.servlet.jsp.tagext.BodyTag;
 
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
 import org.springframework.web.util.JavaScriptUtils;
 
 /**
@@ -45,6 +47,7 @@ public class EscapeBodyTag extends HtmlEscapingAwareTag implements BodyTag {
 
 	private boolean javaScriptEscape = false;
 
+	@Nullable
 	private BodyContent bodyContent;
 
 
@@ -94,6 +97,7 @@ public class EscapeBodyTag extends HtmlEscapingAwareTag implements BodyTag {
 	 * @throws IOException if reading failed
 	 */
 	protected String readBodyContent() throws IOException {
+		Assert.state(this.bodyContent != null, "No BodyContent set");
 		return this.bodyContent.getString();
 	}
 
@@ -104,6 +108,7 @@ public class EscapeBodyTag extends HtmlEscapingAwareTag implements BodyTag {
 	 * @throws IOException if writing failed
 	 */
 	protected void writeBodyContent(String content) throws IOException {
+		Assert.state(this.bodyContent != null, "No BodyContent set");
 		this.bodyContent.getEnclosingWriter().print(content);
 	}
 

spring-webmvc/src/main/java/org/springframework/web/servlet/view/AbstractView.java

@@ -103,6 +103,7 @@ public abstract class AbstractView extends WebApplicationObjectSupport implement
 	 * Return the content type for this view.
 	 */
 	@Override
+	@Nullable
 	public String getContentType() {
 		return this.contentType;
 	}

spring-webmvc/src/main/java/org/springframework/web/servlet/view/script/ScriptTemplateConfigurer.java

@@ -21,6 +21,8 @@ import java.nio.charset.Charset;
 import javax.script.Bindings;
 import javax.script.ScriptEngine;
 
+import org.springframework.lang.Nullable;
+
 /**
  * An implementation of Spring MVC's {@link ScriptTemplateConfig} for creating
  * a {@code ScriptEngine} for use in a web application.
@@ -48,22 +50,31 @@ import javax.script.ScriptEngine;
  */
 public class ScriptTemplateConfigurer implements ScriptTemplateConfig {
 
+	@Nullable
 	private ScriptEngine engine;
 
+	@Nullable
 	private String engineName;
 
+	@Nullable
 	private Boolean sharedEngine;
 
+	@Nullable
 	private String[] scripts;
 
+	@Nullable
 	private String renderObject;
 
+	@Nullable
 	private String renderFunction;
 
+	@Nullable
 	private String contentType;
 
+	@Nullable
 	private Charset charset;
 
+	@Nullable
 	private String resourceLoaderPath;
 
 
@@ -90,11 +101,12 @@ public class ScriptTemplateConfigurer implements ScriptTemplateConfig {
 	 * one (since it implies multiple lazy instantiations of the script engine).
 	 * @see #setEngineName(String)
 	 */
-	public void setEngine(ScriptEngine engine) {
+	public void setEngine(@Nullable ScriptEngine engine) {
 		this.engine = engine;
 	}
 
 	@Override
+	@Nullable
 	public ScriptEngine getEngine() {
 		return this.engine;
 	}
@@ -105,11 +117,12 @@ public class ScriptTemplateConfigurer implements ScriptTemplateConfig {
 	 * You must define {@code engine} or {@code engineName}, not both.
 	 * @see #setEngine(ScriptEngine)
 	 */
-	public void setEngineName(String engineName) {
+	public void setEngineName(@Nullable String engineName) {
 		this.engineName = engineName;
 	}
 
 	@Override
+	@Nullable
 	public String getEngineName() {
 		return this.engineName;
 	}
@@ -127,11 +140,12 @@ public class ScriptTemplateConfigurer implements ScriptTemplateConfig {
 	 * (one per thread).
 	 * @see <a href="http://docs.oracle.com/javase/8/docs/api/javax/script/ScriptEngineFactory.html#getParameter-java.lang.String-">THREADING ScriptEngine parameter<a/>
 	 */
-	public void setSharedEngine(Boolean sharedEngine) {
+	public void setSharedEngine(@Nullable Boolean sharedEngine) {
 		this.sharedEngine = sharedEngine;
 	}
 
 	@Override
+	@Nullable
 	public Boolean isSharedEngine() {
 		return this.sharedEngine;
 	}
@@ -147,11 +161,12 @@ public class ScriptTemplateConfigurer implements ScriptTemplateConfig {
 	 * @see #setResourceLoaderPath
 	 * @see <a href="http://www.webjars.org">WebJars</a>
 	 */
-	public void setScripts(String... scriptNames) {
+	public void setScripts(@Nullable String... scriptNames) {
 		this.scripts = scriptNames;
 	}
 
 	@Override
+	@Nullable
 	public String[] getScripts() {
 		return this.scripts;
 	}
@@ -161,11 +176,12 @@ public class ScriptTemplateConfigurer implements ScriptTemplateConfig {
 	 * For example, in order to call {@code Mustache.render()}, {@code renderObject}
 	 * should be set to {@code "Mustache"} and {@code renderFunction} to {@code "render"}.
 	 */
-	public void setRenderObject(String renderObject) {
+	public void setRenderObject(@Nullable String renderObject) {
 		this.renderObject = renderObject;
 	}
 
 	@Override
+	@Nullable
 	public String getRenderObject() {
 		return this.renderObject;
 	}
@@ -181,11 +197,12 @@ public class ScriptTemplateConfigurer implements ScriptTemplateConfig {
 	 * </ol>
 	 * @see RenderingContext
 	 */
-	public void setRenderFunction(String renderFunction) {
+	public void setRenderFunction(@Nullable String renderFunction) {
 		this.renderFunction = renderFunction;
 	}
 
 	@Override
+	@Nullable
 	public String getRenderFunction() {
 		return this.renderFunction;
 	}
@@ -195,7 +212,7 @@ public class ScriptTemplateConfigurer implements ScriptTemplateConfig {
 	 * ({@code text/html} by default).
 	 * @since 4.2.1
 	 */
-	public void setContentType(String contentType) {
+	public void setContentType(@Nullable String contentType) {
 		this.contentType = contentType;
 	}
 
@@ -204,6 +221,7 @@ public class ScriptTemplateConfigurer implements ScriptTemplateConfig {
 	 * @since 4.2.1
 	 */
 	@Override
+	@Nullable
 	public String getContentType() {
 		return this.contentType;
 	}
@@ -212,11 +230,12 @@ public class ScriptTemplateConfigurer implements ScriptTemplateConfig {
 	 * Set the charset used to read script and template files.
 	 * ({@code UTF-8} by default).
 	 */
-	public void setCharset(Charset charset) {
+	public void setCharset(@Nullable Charset charset) {
 		this.charset = charset;
 	}
 
 	@Override
+	@Nullable
 	public Charset getCharset() {
 		return this.charset;
 	}
@@ -229,11 +248,12 @@ public class ScriptTemplateConfigurer implements ScriptTemplateConfig {
 	 * Relative paths are allowed when running in an ApplicationContext.
 	 * <p>Default is "classpath:".
 	 */
-	public void setResourceLoaderPath(String resourceLoaderPath) {
+	public void setResourceLoaderPath(@Nullable String resourceLoaderPath) {
 		this.resourceLoaderPath = resourceLoaderPath;
 	}
 
 	@Override
+	@Nullable
 	public String getResourceLoaderPath() {
 		return this.resourceLoaderPath;
 	}