Http(Async)Client not actually nullable, plus MethodInterceptor nullability

Issue: SPR-15720

Author: jhoeller

spring-aop/src/main/java/org/springframework/aop/interceptor/AsyncExecutionInterceptor.java

@@ -98,6 +98,7 @@ public AsyncExecutionInterceptor(@Nullable Executor defaultExecutor, AsyncUncaug
 	 * otherwise.
 	 */
 	@Override
+	@Nullable
 	public Object invoke(final MethodInvocation invocation) throws Throwable {
 		Class<?> targetClass = (invocation.getThis() != null ? AopUtils.getTargetClass(invocation.getThis()) : null);
 		Method specificMethod = ClassUtils.getMostSpecificMethod(invocation.getMethod(), targetClass);

spring-aop/src/main/java/org/springframework/aop/support/DelegatePerTargetObjectIntroductionInterceptor.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.
@@ -24,6 +24,7 @@
 import org.springframework.aop.DynamicIntroductionAdvice;
 import org.springframework.aop.IntroductionInterceptor;
 import org.springframework.aop.ProxyMethodInvocation;
+import org.springframework.lang.Nullable;
 import org.springframework.util.ReflectionUtils;
 
 /**
@@ -85,6 +86,7 @@ public DelegatePerTargetObjectIntroductionInterceptor(Class<?> defaultImplType,
 	 * method, which handles introduced interfaces and forwarding to the target.
 	 */
 	@Override
+	@Nullable
 	public Object invoke(MethodInvocation mi) throws Throwable {
 		if (isMethodOnIntroducedInterface(mi)) {
 			Object delegate = getIntroductionDelegateFor(mi.getThis());

spring-aop/src/main/java/org/springframework/aop/support/DelegatingIntroductionInterceptor.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.
@@ -21,6 +21,7 @@
 import org.springframework.aop.DynamicIntroductionAdvice;
 import org.springframework.aop.IntroductionInterceptor;
 import org.springframework.aop.ProxyMethodInvocation;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -100,6 +101,7 @@ private void init(Object delegate) {
 	 * method, which handles introduced interfaces and forwarding to the target.
 	 */
 	@Override
+	@Nullable
 	public Object invoke(MethodInvocation mi) throws Throwable {
 		if (isMethodOnIntroducedInterface(mi)) {
 			// Using the following method rather than direct reflection, we

spring-context/src/main/java/org/springframework/cache/interceptor/CacheInterceptor.java

@@ -22,6 +22,8 @@
 import org.aopalliance.intercept.MethodInterceptor;
 import org.aopalliance.intercept.MethodInvocation;
 
+import org.springframework.lang.Nullable;
+
 /**
  * AOP Alliance MethodInterceptor for declarative cache
  * management using the common Spring caching infrastructure
@@ -42,6 +44,7 @@
 public class CacheInterceptor extends CacheAspectSupport implements MethodInterceptor, Serializable {
 
 	@Override
+	@Nullable
 	public Object invoke(final MethodInvocation invocation) throws Throwable {
 		Method method = invocation.getMethod();
 

spring-context/src/main/java/org/springframework/ejb/access/AbstractSlsbInvokerInterceptor.java

@@ -187,6 +187,7 @@ protected boolean isHomeRefreshable() {
 	 * {@link #invokeInContext}.
 	 */
 	@Override
+	@Nullable
 	public Object invoke(MethodInvocation invocation) throws Throwable {
 		Context ctx = (this.exposeAccessContext ? getJndiTemplate().getContext() : null);
 		try {

spring-context/src/main/java/org/springframework/jmx/access/MBeanClientInterceptor.java

@@ -354,6 +354,7 @@ protected boolean isPrepared() {
 	 * @see #handleConnectFailure
 	 */
 	@Override
+	@Nullable
 	public Object invoke(MethodInvocation invocation) throws Throwable {
 		// Lazily connect to MBeanServer if necessary.
 		synchronized (this.preparationMonitor) {

spring-jms/src/main/java/org/springframework/jms/remoting/JmsInvokerClientInterceptor.java

@@ -192,6 +192,7 @@ public void afterPropertiesSet() {
 
 
 	@Override
+	@Nullable
 	public Object invoke(MethodInvocation methodInvocation) throws Throwable {
 		if (AopUtils.isToStringMethod(methodInvocation.getMethod())) {
 			return "JMS invoker proxy for queue [" + this.queue + "]";

spring-orm/src/main/java/org/springframework/orm/jpa/JpaTransactionManager.java

@@ -420,8 +420,7 @@ public int getTimeout() {
 						conHolder.setTimeoutInSeconds(timeoutToUse);
 					}
 					if (logger.isDebugEnabled()) {
-						logger.debug("Exposing JPA transaction as JDBC transaction [" +
-								conHolder.getConnectionHandle() + "]");
+						logger.debug("Exposing JPA transaction as JDBC transaction [" + conHandle + "]");
 					}
 					TransactionSynchronizationManager.bindResource(getDataSource(), conHolder);
 					txObject.setConnectionHolder(conHolder);
@@ -601,13 +600,16 @@ protected void doCleanupAfterCompletion(Object transaction) {
 		// Remove the JDBC connection holder from the thread, if exposed.
 		if (getDataSource() != null && txObject.hasConnectionHolder()) {
 			TransactionSynchronizationManager.unbindResource(getDataSource());
-			try {
-				getJpaDialect().releaseJdbcConnection(txObject.getConnectionHolder().getConnectionHandle(),
-						txObject.getEntityManagerHolder().getEntityManager());
-			}
-			catch (Exception ex) {
-				// Just log it, to keep a transaction-related exception.
-				logger.error("Could not close JDBC connection after transaction", ex);
+			ConnectionHandle conHandle = txObject.getConnectionHolder().getConnectionHandle();
+			if (conHandle != null) {
+				try {
+					getJpaDialect().releaseJdbcConnection(conHandle,
+							txObject.getEntityManagerHolder().getEntityManager());
+				}
+				catch (Exception ex) {
+					// Just log it, to keep a transaction-related exception.
+					logger.error("Could not close JDBC connection after transaction", ex);
+				}
 			}
 		}
 

spring-tx/src/main/java/org/springframework/transaction/interceptor/TransactionInterceptor.java

@@ -27,6 +27,7 @@
 
 import org.springframework.aop.support.AopUtils;
 import org.springframework.beans.factory.BeanFactory;
+import org.springframework.lang.Nullable;
 import org.springframework.transaction.PlatformTransactionManager;
 
 /**
@@ -86,6 +87,7 @@ public TransactionInterceptor(PlatformTransactionManager ptm, TransactionAttribu
 
 
 	@Override
+	@Nullable
 	public Object invoke(final MethodInvocation invocation) throws Throwable {
 		// Work out the target class: may be {@code null}.
 		// The TransactionAttributeSource should be passed the target class

spring-web/src/main/java/org/springframework/http/client/HttpComponentsAsyncClientHttpRequestFactory.java

@@ -33,7 +33,6 @@
 
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.http.HttpMethod;
-import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -51,7 +50,6 @@
 public class HttpComponentsAsyncClientHttpRequestFactory extends HttpComponentsClientHttpRequestFactory
 		implements AsyncClientHttpRequestFactory, InitializingBean {
 
-	@Nullable
 	private HttpAsyncClient asyncClient;
 
 
@@ -72,7 +70,7 @@ public HttpComponentsAsyncClientHttpRequestFactory() {
 	 */
 	public HttpComponentsAsyncClientHttpRequestFactory(HttpAsyncClient asyncClient) {
 		super();
-		setAsyncClient(asyncClient);
+		this.asyncClient = asyncClient;
 	}
 
 	/**
@@ -82,7 +80,7 @@ public HttpComponentsAsyncClientHttpRequestFactory(HttpAsyncClient asyncClient)
 	 */
 	public HttpComponentsAsyncClientHttpRequestFactory(CloseableHttpAsyncClient asyncClient) {
 		super();
-		setAsyncClient(asyncClient);
+		this.asyncClient = asyncClient;
 	}
 
 	/**
@@ -94,7 +92,7 @@ public HttpComponentsAsyncClientHttpRequestFactory(CloseableHttpAsyncClient asyn
 	 */
 	public HttpComponentsAsyncClientHttpRequestFactory(HttpClient httpClient, HttpAsyncClient asyncClient) {
 		super(httpClient);
-		setAsyncClient(asyncClient);
+		this.asyncClient = asyncClient;
 	}
 
 	/**
@@ -107,7 +105,7 @@ public HttpComponentsAsyncClientHttpRequestFactory(
 			CloseableHttpClient httpClient, CloseableHttpAsyncClient asyncClient) {
 
 		super(httpClient);
-		setAsyncClient(asyncClient);
+		this.asyncClient = asyncClient;
 	}
 
 
@@ -128,7 +126,6 @@ public void setAsyncClient(HttpAsyncClient asyncClient) {
 	 * @since 4.3.10
 	 * @see #getHttpClient()
 	 */
-	@Nullable
 	public HttpAsyncClient getAsyncClient() {
 		return this.asyncClient;
 	}
@@ -150,7 +147,7 @@ public void setHttpAsyncClient(CloseableHttpAsyncClient asyncClient) {
 	 */
 	@Deprecated
 	public CloseableHttpAsyncClient getHttpAsyncClient() {
-		Assert.state(this.asyncClient == null || this.asyncClient instanceof CloseableHttpAsyncClient,
+		Assert.state(this.asyncClient instanceof CloseableHttpAsyncClient,
 				"No CloseableHttpAsyncClient - use getAsyncClient() instead");
 		return (CloseableHttpAsyncClient) this.asyncClient;
 	}
@@ -163,7 +160,6 @@ public void afterPropertiesSet() {
 
 	private HttpAsyncClient startAsyncClient() {
         HttpAsyncClient client = getAsyncClient();
-		Assert.state(client != null, "No HttpAsyncClient set");
 		if (client instanceof CloseableHttpAsyncClient) {
 			CloseableHttpAsyncClient closeableAsyncClient = (CloseableHttpAsyncClient) client;
 			if (!closeableAsyncClient.isRunning()) {

spring-web/src/main/java/org/springframework/http/client/HttpComponentsClientHttpRequestFactory.java

@@ -59,7 +59,6 @@
  */
 public class HttpComponentsClientHttpRequestFactory implements ClientHttpRequestFactory, DisposableBean {
 
-	@Nullable
 	private HttpClient httpClient;
 
 	@Nullable
@@ -82,7 +81,7 @@ public HttpComponentsClientHttpRequestFactory() {
 	 * @param httpClient the HttpClient instance to use for this request factory
 	 */
 	public HttpComponentsClientHttpRequestFactory(HttpClient httpClient) {
-		setHttpClient(httpClient);
+		this.httpClient = httpClient;
 	}
 
 
@@ -99,7 +98,6 @@ public void setHttpClient(HttpClient httpClient) {
 	 * Return the {@code HttpClient} used for
 	 * {@linkplain #createRequest(URI, HttpMethod) synchronous execution}.
 	 */
-	@Nullable
 	public HttpClient getHttpClient() {
 		return this.httpClient;
 	}
@@ -156,7 +154,6 @@ public void setBufferRequestBody(boolean bufferRequestBody) {
 	@Override
 	public ClientHttpRequest createRequest(URI uri, HttpMethod httpMethod) throws IOException {
 		HttpClient client = getHttpClient();
-		Assert.state(client != null, "No HttpClient set");
 
 		HttpUriRequest httpRequest = createHttpUriRequest(httpMethod, uri);
 		postProcessHttpRequest(httpRequest);

spring-web/src/main/java/org/springframework/http/codec/json/Jackson2JsonEncoder.java

@@ -43,6 +43,7 @@
  */
 public class Jackson2JsonEncoder extends AbstractJackson2Encoder {
 
+	@Nullable
 	private final PrettyPrinter ssePrettyPrinter;
 
 

spring-web/src/main/java/org/springframework/remoting/jaxws/JaxWsPortClientInterceptor.java

@@ -494,6 +494,7 @@ protected Object getPortStub() {
 
 
 	@Override
+	@Nullable
 	public Object invoke(MethodInvocation invocation) throws Throwable {
 		if (AopUtils.isToStringMethod(invocation.getMethod())) {
 			return "JAX-WS proxy for port [" + getPortName() + "] of service [" + getServiceName() + "]";

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

@@ -753,6 +753,7 @@ else if (ReflectionUtils.isObjectMethod(method)) {
 		}
 
 		@Override
+		@Nullable
 		public Object invoke(org.aopalliance.intercept.MethodInvocation inv) throws Throwable {
 			return intercept(inv.getThis(), inv.getMethod(), inv.getArguments(), null);
 		}