diff --git a/spring-integration-jdbc/src/main/java/org/springframework/integration/jdbc/JdbcMessageStore.java b/spring-integration-jdbc/src/main/java/org/springframework/integration/jdbc/JdbcMessageStore.java
index 3cdf63bd40..12b74d39bd 100644
--- a/spring-integration-jdbc/src/main/java/org/springframework/integration/jdbc/JdbcMessageStore.java
+++ b/spring-integration-jdbc/src/main/java/org/springframework/integration/jdbc/JdbcMessageStore.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.
@@ -639,7 +639,8 @@ public class JdbcMessageStore extends AbstractMessageGroupStore implements Messa
 	protected Message<?> doPollForMessage(String groupIdKey) {
 		List<Message<?>> messages = this.jdbcTemplate.query(getQuery(Query.POLL_FROM_GROUP), this.mapper,
 				groupIdKey, this.region, groupIdKey, this.region);
-		Assert.isTrue(messages.size() == 0 || messages.size() == 1);
+		Assert.state(messages.size() < 2,
+				() -> "The query must return zero or 1 row; got " + messages.size() + " rows");
 		if (messages.size() > 0) {
 			return messages.get(0);
 		}
diff --git a/spring-integration-jdbc/src/main/java/org/springframework/integration/jdbc/store/JdbcChannelMessageStore.java b/spring-integration-jdbc/src/main/java/org/springframework/integration/jdbc/store/JdbcChannelMessageStore.java
index 0a97fd0e61..48c10cb49d 100644
--- a/spring-integration-jdbc/src/main/java/org/springframework/integration/jdbc/store/JdbcChannelMessageStore.java
+++ b/spring-integration-jdbc/src/main/java/org/springframework/integration/jdbc/store/JdbcChannelMessageStore.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.
@@ -52,9 +52,6 @@ import org.springframework.integration.store.MessageGroupStore;
 import org.springframework.integration.store.MessageStore;
 import org.springframework.integration.store.PriorityCapableChannelMessageStore;
 import org.springframework.integration.store.SimpleMessageGroupFactory;
-import org.springframework.integration.support.DefaultMessageBuilderFactory;
-import org.springframework.integration.support.MessageBuilderFactory;
-import org.springframework.integration.support.utils.IntegrationUtils;
 import org.springframework.integration.transaction.TransactionSynchronizationFactory;
 import org.springframework.integration.util.UUIDConverter;
 import org.springframework.jdbc.core.JdbcOperations;
@@ -135,8 +132,6 @@ public class JdbcChannelMessageStore implements PriorityCapableChannelMessageSto
 	@Deprecated
 	public static final String CREATED_DATE_KEY = JdbcChannelMessageStore.class.getSimpleName() + ".CREATED_DATE";
 
-	private volatile MessageBuilderFactory messageBuilderFactory = new DefaultMessageBuilderFactory();
-
 	private volatile String region = DEFAULT_REGION;
 
 	private volatile String tablePrefix = DEFAULT_TABLE_PREFIX;
@@ -402,9 +397,6 @@ public class JdbcChannelMessageStore implements PriorityCapableChannelMessageSto
 			logger.warn("The jdbcTemplate's fetch size is not 1. This may cause FIFO issues with Oracle databases.");
 		}
 
-		if (this.beanFactory != null) {
-			this.messageBuilderFactory = IntegrationUtils.getMessageBuilderFactory(this.beanFactory);
-		}
 		this.jdbcTemplate.afterPropertiesSet();
 	}
 
@@ -419,7 +411,6 @@ public class JdbcChannelMessageStore implements PriorityCapableChannelMessageSto
 	 * @param message a message
 	 */
 	@Override
-	@SuppressWarnings("unchecked")
 	public MessageGroup addMessageToGroup(Object groupId, final Message<?> message) {
 
 		String groupKey = getKey(groupId);
@@ -600,7 +591,8 @@ public class JdbcChannelMessageStore implements PriorityCapableChannelMessageSto
 		}
 
 
-		Assert.isTrue(messages.size() == 0 || messages.size() == 1);
+		Assert.state(messages.size() < 2,
+				() -> "The query must return zero or 1 row; got " + messages.size() + " rows");
 		if (messages.size() > 0) {
 
 			final Message<?> message = messages.get(0);
diff --git a/spring-integration-mqtt/src/main/java/org/springframework/integration/mqtt/support/DefaultPahoMessageConverter.java b/spring-integration-mqtt/src/main/java/org/springframework/integration/mqtt/support/DefaultPahoMessageConverter.java
index 9603ef62b9..0ac7ab0aa1 100644
--- a/spring-integration-mqtt/src/main/java/org/springframework/integration/mqtt/support/DefaultPahoMessageConverter.java
+++ b/spring-integration-mqtt/src/main/java/org/springframework/integration/mqtt/support/DefaultPahoMessageConverter.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.
@@ -177,7 +177,9 @@ public class DefaultPahoMessageConverter implements MqttMessageConverter, BeanFa
 
 	@Override
 	public Message<?> toMessage(Object mqttMessage, MessageHeaders headers) {
-		Assert.isInstanceOf(MqttMessage.class, mqttMessage);
+		Assert.isInstanceOf(MqttMessage.class, mqttMessage,
+				() -> "This converter can only convert an 'MqttMessage'; received: "
+						+ mqttMessage.getClass().getName());
 		return toMessage(null, (MqttMessage) mqttMessage);
 	}
 
@@ -236,7 +238,10 @@ public class DefaultPahoMessageConverter implements MqttMessageConverter, BeanFa
 	 */
 	protected byte[] messageToMqttBytes(Message<?> message) {
 		Object payload = message.getPayload();
-		Assert.isTrue(payload instanceof byte[] || payload instanceof String);
+		Assert.isTrue(payload instanceof byte[] || payload instanceof String,
+				() -> "This default converter can only handle 'byte[]' or 'String' payloads; consider adding a "
+						+ "transformer to your flow definition, or subclass this converter for "
+						+ payload.getClass().getName() + " payloads");
 		byte[] payloadBytes;
 		if (payload instanceof String) {
 			try {