diff --git a/spring-integration-mongodb/src/main/java/org/springframework/integration/mongodb/store/AbstractConfigurableMongoDbMessageStore.java b/spring-integration-mongodb/src/main/java/org/springframework/integration/mongodb/store/AbstractConfigurableMongoDbMessageStore.java
index cfc917e0a5..349bdc0182 100644
--- a/spring-integration-mongodb/src/main/java/org/springframework/integration/mongodb/store/AbstractConfigurableMongoDbMessageStore.java
+++ b/spring-integration-mongodb/src/main/java/org/springframework/integration/mongodb/store/AbstractConfigurableMongoDbMessageStore.java
@@ -150,13 +150,15 @@ public abstract class AbstractConfigurableMongoDbMessageStore extends AbstractMe
 
 		indexOperations.ensureIndex(new Index(MessageDocumentFields.MESSAGE_ID, Sort.Direction.ASC));
 
-		indexOperations.ensureIndex(new Index(MessageDocumentFields.GROUP_ID, Sort.Direction.ASC)
-				.on(MessageDocumentFields.MESSAGE_ID, Sort.Direction.ASC)
-				.unique());
+		indexOperations.ensureIndex(
+				new Index(MessageDocumentFields.GROUP_ID, Sort.Direction.ASC)
+						.on(MessageDocumentFields.MESSAGE_ID, Sort.Direction.ASC)
+						.unique());
 
-		indexOperations.ensureIndex(new Index(MessageDocumentFields.GROUP_ID, Sort.Direction.ASC)
-				.on(MessageDocumentFields.LAST_MODIFIED_TIME, Sort.Direction.DESC)
-				.on(MessageDocumentFields.SEQUENCE, Sort.Direction.DESC));
+		indexOperations.ensureIndex(
+				new Index(MessageDocumentFields.GROUP_ID, Sort.Direction.ASC)
+						.on(MessageDocumentFields.LAST_MODIFIED_TIME, Sort.Direction.DESC)
+						.on(MessageDocumentFields.SEQUENCE, Sort.Direction.DESC));
 	}
 
 	public Message<?> getMessage(UUID id) {
@@ -198,14 +200,15 @@ public abstract class AbstractConfigurableMongoDbMessageStore extends AbstractMe
 	 * The {@link #SEQUENCE_NAME} document is created on demand.
 	 * @return the next sequence value.
 	 */
-	protected int getNextId() {
+	protected long getNextId() {
 		Query query = Query.query(Criteria.where("_id").is(SEQUENCE_NAME));
 		query.fields().include(MessageDocumentFields.SEQUENCE);
-		return (Integer) this.mongoTemplate.findAndModify(query,
-				new Update().inc(MessageDocumentFields.SEQUENCE, 1),
+		return ((Number) this.mongoTemplate.findAndModify(query,
+				new Update().inc(MessageDocumentFields.SEQUENCE, 1L),
 				FindAndModifyOptions.options().returnNew(true).upsert(true),
 				Map.class, this.collectionName)
-				.get(MessageDocumentFields.SEQUENCE); // NOSONAR - never returns null
+				.get(MessageDocumentFields.SEQUENCE))  // NOSONAR - never returns null
+				.longValue();
 	}
 
 	protected void addMessageDocument(final MessageDocument document) {
diff --git a/spring-integration-mongodb/src/main/java/org/springframework/integration/mongodb/store/MessageDocument.java b/spring-integration-mongodb/src/main/java/org/springframework/integration/mongodb/store/MessageDocument.java
index 3f6fc9b3da..0507ba4cd5 100644
--- a/spring-integration-mongodb/src/main/java/org/springframework/integration/mongodb/store/MessageDocument.java
+++ b/spring-integration-mongodb/src/main/java/org/springframework/integration/mongodb/store/MessageDocument.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2019 the original author or authors.
+ * Copyright 2014-2020 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.
@@ -61,7 +61,7 @@ public class MessageDocument {
 
 	private Integer lastReleasedSequence = 0;
 
-	private int sequence;
+	private long sequence;
 
 	public MessageDocument(Message<?> message) {
 		this(message, message.getHeaders().getId());
@@ -139,7 +139,7 @@ public class MessageDocument {
 		this.lastReleasedSequence = lastReleasedSequence;
 	}
 
-	public void setSequence(int sequence) {
+	public void setSequence(long sequence) {
 		this.sequence = sequence;
 	}
 
@@ -151,7 +151,7 @@ public class MessageDocument {
 		return this.groupId;
 	}
 
-	public int getSequence() {
+	public long getSequence() {
 		return this.sequence;
 	}
 
diff --git a/spring-integration-mongodb/src/main/java/org/springframework/integration/mongodb/store/MongoDbChannelMessageStore.java b/spring-integration-mongodb/src/main/java/org/springframework/integration/mongodb/store/MongoDbChannelMessageStore.java
index 17173ddc2f..4e90dcf733 100644
--- a/spring-integration-mongodb/src/main/java/org/springframework/integration/mongodb/store/MongoDbChannelMessageStore.java
+++ b/spring-integration-mongodb/src/main/java/org/springframework/integration/mongodb/store/MongoDbChannelMessageStore.java
@@ -49,6 +49,9 @@ import org.springframework.util.Assert;
 public class MongoDbChannelMessageStore extends AbstractConfigurableMongoDbMessageStore
 		implements PriorityCapableChannelMessageStore {
 
+	/**
+	 * The default conventional collection name.
+	 */
 	public static final String DEFAULT_COLLECTION_NAME = "channelMessages";
 
 	private boolean priorityEnabled;
@@ -65,7 +68,9 @@ public class MongoDbChannelMessageStore extends AbstractConfigurableMongoDbMessa
 		this(mongoDbFactory, null, DEFAULT_COLLECTION_NAME);
 	}
 
-	public MongoDbChannelMessageStore(MongoDatabaseFactory mongoDbFactory, MappingMongoConverter mappingMongoConverter) {
+	public MongoDbChannelMessageStore(MongoDatabaseFactory mongoDbFactory,
+			MappingMongoConverter mappingMongoConverter) {
+
 		this(mongoDbFactory, mappingMongoConverter, DEFAULT_COLLECTION_NAME);
 	}
 
@@ -75,6 +80,7 @@ public class MongoDbChannelMessageStore extends AbstractConfigurableMongoDbMessa
 
 	public MongoDbChannelMessageStore(MongoDatabaseFactory mongoDbFactory, MappingMongoConverter mappingMongoConverter,
 			String collectionName) {
+
 		super(mongoDbFactory, mappingMongoConverter, collectionName);
 	}
 
@@ -90,7 +96,8 @@ public class MongoDbChannelMessageStore extends AbstractConfigurableMongoDbMessa
 	@Override
 	public void afterPropertiesSet() {
 		super.afterPropertiesSet();
-		getMongoTemplate().indexOps(this.collectionName)
+		getMongoTemplate()
+				.indexOps(this.collectionName)
 				.ensureIndex(new Index(MessageDocumentFields.GROUP_ID, Sort.Direction.ASC)
 						.on(MessageDocumentFields.PRIORITY, Sort.Direction.DESC)
 						.on(MessageDocumentFields.LAST_MODIFIED_TIME, Sort.Direction.ASC)
@@ -109,10 +116,10 @@ public class MongoDbChannelMessageStore extends AbstractConfigurableMongoDbMessa
 		if (this.priorityEnabled) {
 			document.setPriority(message.getHeaders().get(IntegrationMessageHeaderAccessor.PRIORITY, Integer.class));
 		}
-		document.setSequence(this.getNextId());
+		document.setSequence(getNextId());
 
-		this.addMessageDocument(document);
-		return this.getMessageGroup(groupId);
+		addMessageDocument(document);
+		return getMessageGroup(groupId);
 	}
 
 	/**
diff --git a/spring-integration-mongodb/src/main/java/org/springframework/integration/mongodb/store/MongoDbMessageStore.java b/spring-integration-mongodb/src/main/java/org/springframework/integration/mongodb/store/MongoDbMessageStore.java
index f73c168a06..2a9277a206 100644
--- a/spring-integration-mongodb/src/main/java/org/springframework/integration/mongodb/store/MongoDbMessageStore.java
+++ b/spring-integration-mongodb/src/main/java/org/springframework/integration/mongodb/store/MongoDbMessageStore.java
@@ -470,14 +470,15 @@ public class MongoDbMessageStore extends AbstractMessageGroupStore
 		this.template.findAndModify(query, update, FindAndModifyOptions.none(), Map.class, this.collectionName);
 	}
 
-	private int getNextId() {
+	private long getNextId() {
 		Query query = Query.query(Criteria.where("_id").is(SEQUENCE_NAME));
 		query.fields().include(SEQUENCE);
-		return (Integer) this.template.findAndModify(query,
-				new Update().inc(SEQUENCE, 1),
+		return ((Number) this.template.findAndModify(query,
+				new Update().inc(SEQUENCE, 1L),
 				FindAndModifyOptions.options().returnNew(true).upsert(true),
-				Map.class,
-				this.collectionName).get(SEQUENCE); // NOSONAR - never returns null
+				Map.class, this.collectionName)
+				.get(SEQUENCE))  // NOSONAR - never returns null
+				.longValue();
 	}
 
 	@SuppressWarnings(UNCHECKED)
@@ -848,7 +849,7 @@ public class MongoDbMessageStore extends AbstractMessageGroupStore
 		private volatile boolean _group_complete; // NOSONAR name
 
 		@SuppressWarnings(UNUSED)
-		private int sequence;
+		private long sequence;
 
 		MessageWrapper(Message<?> message) {
 			Assert.notNull(message, "'message' must not be null");
@@ -917,7 +918,7 @@ public class MongoDbMessageStore extends AbstractMessageGroupStore
 			this._group_complete = completedGroup;
 		}
 
-		public void set_Sequence(int sequence) { // NOSONAR name
+		public void set_Sequence(long sequence) { // NOSONAR name
 			this.sequence = sequence;
 		}