Sonar fixes

Critical issues for `o.s.i.j*` (except `jdbc`).

Author: garyrussell

spring-integration-core/src/main/java/org/springframework/integration/core/MessageSource.java

@@ -16,6 +16,7 @@
 
 package org.springframework.integration.core;
 
+import org.springframework.lang.Nullable;
 import org.springframework.messaging.Message;
 
 /**
@@ -31,6 +32,7 @@ public interface MessageSource<T> {
 	 * Returns <code>null</code> if no message is available.
 	 * @return The message or null.
 	 */
+	@Nullable
 	Message<T> receive();
 
 }

spring-integration-core/src/main/java/org/springframework/integration/endpoint/AbstractMessageSource.java

@@ -31,6 +31,7 @@
 import org.springframework.integration.support.management.metrics.CounterFacade;
 import org.springframework.integration.support.management.metrics.MetricsCaptor;
 import org.springframework.integration.util.AbstractExpressionEvaluator;
+import org.springframework.lang.Nullable;
 import org.springframework.messaging.Message;
 import org.springframework.messaging.MessagingException;
 import org.springframework.util.CollectionUtils;
@@ -231,6 +232,7 @@ private Map<String, Object> evaluateHeaders() {
 	 * also can be {@link AbstractIntegrationMessageBuilder} which is used for additional headers population.
 	 * @return The value returned.
 	 */
+	@Nullable
 	protected abstract Object doReceive();
 
 	@Override

spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/connection/CachingClientConnectionFactory.java

@@ -393,7 +393,9 @@ private final class CachedConnection extends TcpConnectionInterceptorSupport {
 
 		private final AtomicBoolean released = new AtomicBoolean();
 
-		private CachedConnection(TcpConnectionSupport connection, @Nullable TcpListener tcpListener) {
+		private CachedConnection(TcpConnectionSupport connection, // NOSONAR false positive, not marked @Nullable
+				@Nullable TcpListener tcpListener) {
+
 			super.setTheConnection(connection);
 			registerListener(tcpListener);
 		}

spring-integration-jms/src/main/java/org/springframework/integration/jms/JmsDestinationPollingSource.java

@@ -24,6 +24,7 @@
 import org.springframework.integration.jms.util.JmsAdapterUtils;
 import org.springframework.integration.support.AbstractIntegrationMessageBuilder;
 import org.springframework.jms.core.JmsTemplate;
+import org.springframework.jms.support.converter.MessageConverter;
 import org.springframework.messaging.Message;
 import org.springframework.messaging.MessagingException;
 import org.springframework.util.Assert;
@@ -131,7 +132,10 @@ protected Object doReceive() {
 			Map<String, Object> mappedHeaders = this.headerMapper.toHeaders(jmsMessage);
 			Object object = jmsMessage;
 			if (this.extractPayload) {
-				object = this.jmsTemplate.getMessageConverter().fromMessage(jmsMessage);
+				MessageConverter converter = this.jmsTemplate.getMessageConverter();
+				if (converter != null) {
+					object = converter.fromMessage(jmsMessage);
+				}
 			}
 			AbstractIntegrationMessageBuilder<?> builder =
 					(object instanceof Message)

spring-integration-jms/src/main/java/org/springframework/integration/jms/SubscribableJmsChannel.java

@@ -33,6 +33,7 @@
 import org.springframework.integration.support.MessageBuilderFactory;
 import org.springframework.jms.core.JmsTemplate;
 import org.springframework.jms.listener.AbstractMessageListenerContainer;
+import org.springframework.jms.support.converter.MessageConverter;
 import org.springframework.messaging.Message;
 import org.springframework.messaging.MessageDeliveryException;
 import org.springframework.messaging.MessageHandler;
@@ -206,14 +207,19 @@ private static final class DispatchingMessageListener implements MessageListener
 		public void onMessage(javax.jms.Message message) {
 			Message<?> messageToSend = null;
 			try {
-				Object converted = this.jmsTemplate.getMessageConverter().fromMessage(message);
+				MessageConverter converter = this.jmsTemplate.getMessageConverter();
+				Object converted = null;
+				if (converter != null) {
+					converted = converter.fromMessage(message);
+				}
 				if (converted != null) {
 					messageToSend = (converted instanceof Message<?>) ? (Message<?>) converted
 							: this.messageBuilderFactory.withPayload(converted).build();
 					this.dispatcher.dispatch(messageToSend);
 				}
 				else if (this.logger.isWarnEnabled()) {
-					this.logger.warn("MessageConverter returned null, no Message to dispatch");
+					this.logger.warn("No converter found, or converter returned null for: " + message
+							+ ", no Message to dispatch");
 				}
 			}
 			catch (MessageDispatchingException e) {

spring-integration-jms/src/main/java/org/springframework/integration/jms/config/JmsChannelFactoryBean.java

@@ -24,6 +24,7 @@
 import javax.jms.ExceptionListener;
 import javax.jms.Session;
 
+import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.BeanNameAware;
 import org.springframework.beans.factory.DisposableBean;
 import org.springframework.beans.factory.config.AbstractFactoryBean;
@@ -392,8 +393,9 @@ protected AbstractJmsChannel createInstance() throws Exception {
 			this.channel.setInterceptors(this.interceptors);
 		}
 		this.channel.setBeanName(this.beanName);
-		if (this.getBeanFactory() != null) {
-			this.channel.setBeanFactory(this.getBeanFactory());
+		BeanFactory beanFactory = this.getBeanFactory();
+		if (beanFactory != null) {
+			this.channel.setBeanFactory(beanFactory);
 		}
 		this.channel.afterPropertiesSet();
 		return this.channel;

spring-integration-jms/src/main/java/org/springframework/integration/jms/dsl/JmsPollableMessageChannelSpec.java

@@ -26,13 +26,15 @@
 import org.springframework.integration.jms.config.JmsChannelFactoryBean;
 import org.springframework.jms.support.converter.MessageConverter;
 import org.springframework.jms.support.destination.DestinationResolver;
+import org.springframework.lang.Nullable;
 
 /**
  * A {@link MessageChannelSpec} for an {@link AbstractJmsChannel}.
  *
  * @param <S> the target {@link JmsPollableMessageChannelSpec} implementation type.
  *
  * @author Artem Bilan
+ * @author Gary Russell
  *
  * @since 5.0
  */
@@ -53,8 +55,10 @@ public class JmsPollableMessageChannelSpec<S extends JmsPollableMessageChannelSp
 	}
 
 	@Override
-	protected S id(String id) {
-		this.jmsChannelFactoryBean.setBeanName(id);
+	protected S id(@Nullable String id) {
+		if (id != null) {
+			this.jmsChannelFactoryBean.setBeanName(id);
+		}
 		return super.id(id);
 	}
 

spring-integration-jmx/src/main/java/org/springframework/integration/jmx/OperationInvokingMessageHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -222,7 +222,7 @@ private String resolveOperationName(Message<?> message) {
 
 	@SuppressWarnings({ "unchecked", "rawtypes" })
 	private Map<String, Object> resolveParameters(Message<?> message) {
-		Map<String, Object> map = null;
+		Map<String, Object> map;
 		if (message.getPayload() instanceof Map) {
 			map = (Map<String, Object>) message.getPayload();
 		}
@@ -233,11 +233,8 @@ else if (message.getPayload() != null && message.getPayload().getClass().isArray
 			map = this.createParameterMapFromList(
 					Arrays.asList(ObjectUtils.toObjectArray(message.getPayload())));
 		}
-		else if (message.getPayload() != null) {
-			map = this.createParameterMapFromList(Collections.singletonList(message.getPayload()));
-		}
 		else {
-			map = Collections.EMPTY_MAP;
+			map = this.createParameterMapFromList(Collections.singletonList(message.getPayload()));
 		}
 		return map;
 	}

spring-integration-jpa/src/main/java/org/springframework/integration/jpa/outbound/JpaOutboundGatewayFactoryBean.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -20,6 +20,7 @@
 
 import org.aopalliance.aop.Advice;
 
+import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.beans.factory.config.AbstractFactoryBean;
 import org.springframework.integration.jpa.core.JpaExecutor;
@@ -132,7 +133,10 @@ protected JpaOutboundGateway createInstance() {
 		if (this.adviceChain != null) {
 			jpaOutboundGateway.setAdviceChain(this.adviceChain);
 		}
-		jpaOutboundGateway.setBeanFactory(this.getBeanFactory());
+		BeanFactory beanFactory = getBeanFactory();
+		if (beanFactory != null) {
+			jpaOutboundGateway.setBeanFactory(beanFactory);
+		}
 		jpaOutboundGateway.afterPropertiesSet();
 		return jpaOutboundGateway;
 	}

spring-integration-jpa/src/main/java/org/springframework/integration/jpa/support/JpaParameter.java

@@ -67,7 +67,7 @@ public JpaParameter(String name, @Nullable Object value, @Nullable String expres
 
 		this.name = name;
 		this.value = value;
-		this.setExpression(expression);
+		setExpression(expression);
 	}
 
 	/**
@@ -79,7 +79,7 @@ public JpaParameter(String name, @Nullable Object value, @Nullable String expres
 	 */
 	public JpaParameter(@Nullable Object value, @Nullable String expression) {
 		this.value = value;
-		this.setExpression(expression);
+		setExpression(expression);
 	}
 
 	public String getName() {
@@ -90,6 +90,7 @@ public void setName(String name) {
 		this.name = name;
 	}
 
+	@Nullable
 	public Object getValue() {
 		return this.value;
 	}
@@ -98,22 +99,27 @@ public void setValue(Object value) {
 		this.value = value;
 	}
 
+	@Nullable
 	public String getExpression() {
 		return this.expression;
 	}
 
+	@Nullable
 	public Expression getSpelExpression() {
 		return this.spelExpression;
 	}
 
+	@Nullable
 	public Expression getProjectionExpression() {
 		return this.projectionExpression;
 	}
 
-	public final void setExpression(String expression) {
-		this.expression = expression;
-		this.spelExpression = PARSER.parseExpression(expression);
-		this.projectionExpression = PARSER.parseExpression("#root.![" + expression + "]");
+	public final void setExpression(@Nullable String expression) {
+		if (expression != null) {
+			this.expression = expression;
+			this.spelExpression = PARSER.parseExpression(expression);
+			this.projectionExpression = PARSER.parseExpression("#root.![" + expression + "]");
+		}
 	}
 
 	@Override