diff --git a/spring-integration-cassandra/src/main/java/org/springframework/integration/cassandra/config/xml/package-info.java b/spring-integration-cassandra/src/main/java/org/springframework/integration/cassandra/config/xml/package-info.java
index 521362d517..30b9f7fbff 100644
--- a/spring-integration-cassandra/src/main/java/org/springframework/integration/cassandra/config/xml/package-info.java
+++ b/spring-integration-cassandra/src/main/java/org/springframework/integration/cassandra/config/xml/package-info.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2022 the original author or authors.
+ * Copyright 2022-2025 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.
@@ -17,4 +17,5 @@
 /**
  * Provides classes for Cassandra parsers and namespace handlers.
  */
+@org.jspecify.annotations.NullMarked
 package org.springframework.integration.cassandra.config.xml;
diff --git a/spring-integration-cassandra/src/main/java/org/springframework/integration/cassandra/dsl/package-info.java b/spring-integration-cassandra/src/main/java/org/springframework/integration/cassandra/dsl/package-info.java
index 788490080d..4bd41357f0 100644
--- a/spring-integration-cassandra/src/main/java/org/springframework/integration/cassandra/dsl/package-info.java
+++ b/spring-integration-cassandra/src/main/java/org/springframework/integration/cassandra/dsl/package-info.java
@@ -1,6 +1,5 @@
 /**
  * Provides Apache Cassandra Components support for the Java DSL.
  */
-@org.springframework.lang.NonNullApi
-@org.springframework.lang.NonNullFields
+@org.jspecify.annotations.NullMarked
 package org.springframework.integration.cassandra.dsl;
diff --git a/spring-integration-cassandra/src/main/java/org/springframework/integration/cassandra/outbound/CassandraMessageHandler.java b/spring-integration-cassandra/src/main/java/org/springframework/integration/cassandra/outbound/CassandraMessageHandler.java
index 76ac5d6a66..0b5764177d 100644
--- a/spring-integration-cassandra/src/main/java/org/springframework/integration/cassandra/outbound/CassandraMessageHandler.java
+++ b/spring-integration-cassandra/src/main/java/org/springframework/integration/cassandra/outbound/CassandraMessageHandler.java
@@ -27,6 +27,7 @@ import com.datastax.oss.driver.api.core.cql.BatchType;
 import com.datastax.oss.driver.api.core.cql.SimpleStatement;
 import com.datastax.oss.driver.api.core.cql.Statement;
 import com.datastax.oss.driver.api.querybuilder.QueryBuilder;
+import org.jspecify.annotations.Nullable;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
@@ -50,7 +51,6 @@ import org.springframework.integration.expression.ExpressionUtils;
 import org.springframework.integration.handler.AbstractReplyProducingMessageHandler;
 import org.springframework.integration.handler.ExpressionEvaluatingMessageProcessor;
 import org.springframework.integration.handler.MessageProcessor;
-import org.springframework.lang.Nullable;
 import org.springframework.messaging.Message;
 import org.springframework.util.Assert;
 
@@ -85,8 +85,10 @@ public class CassandraMessageHandler extends AbstractReplyProducingMessageHandle
 	 */
 	private WriteOptions writeOptions;
 
+	@SuppressWarnings("NullAway.Init")
 	private ReactiveSessionMessageCallback sessionMessageCallback;
 
+	@SuppressWarnings("NullAway.Init")
 	private EvaluationContext evaluationContext;
 
 	public CassandraMessageHandler(ReactiveCassandraOperations cassandraOperations) {
@@ -164,10 +166,13 @@ public class CassandraMessageHandler extends AbstractReplyProducingMessageHandle
 	public void setStatementProcessor(MessageProcessor<Statement<?>> statementProcessor) {
 		Assert.notNull(statementProcessor, "'statementProcessor' must not be null.");
 		this.sessionMessageCallback =
-				(session, requestMessage) ->
-						session.execute(
-								QueryOptionsUtil.addQueryOptions(statementProcessor.processMessage(requestMessage),
-										this.writeOptions));
+				(session, requestMessage) -> {
+					Statement<?> statement = statementProcessor.processMessage(requestMessage);
+					Assert.notNull(statement, "Statement must not be null");
+					return session.execute(
+							QueryOptionsUtil.addQueryOptions(statement,
+									this.writeOptions));
+				};
 		this.mode = Type.STATEMENT;
 	}
 
@@ -191,6 +196,7 @@ public class CassandraMessageHandler extends AbstractReplyProducingMessageHandle
 	}
 
 	@Override
+	@Nullable
 	protected Object handleRequestMessage(Message<?> requestMessage) {
 		Object payload = requestMessage.getPayload();
 
@@ -220,7 +226,8 @@ public class CassandraMessageHandler extends AbstractReplyProducingMessageHandle
 
 	@SuppressWarnings("unchecked")
 	private Mono<? extends WriteResult> handleInsert(Object payload) {
-		if (this.ingestQuery != null) {
+		final String localIngestQuery = this.ingestQuery;
+		if (localIngestQuery != null) {
 			Assert.isInstanceOf(List.class, payload,
 					"to perform 'ingest' the 'payload' must be of 'List<List<?>>' type.");
 			List<?> list = (List<?>) payload;
@@ -232,7 +239,7 @@ public class CassandraMessageHandler extends AbstractReplyProducingMessageHandle
 			return this.cassandraOperations.getReactiveCqlOperations()
 					.execute((ReactiveSessionCallback<WriteResult>) session ->
 							session.prepare(
-											QueryOptionsUtil.addQueryOptions(SimpleStatement.newInstance(this.ingestQuery),
+											QueryOptionsUtil.addQueryOptions(SimpleStatement.newInstance(localIngestQuery),
 													this.writeOptions))
 									.flatMapMany(s ->
 											Flux.fromIterable(rows)
diff --git a/spring-integration-cassandra/src/main/java/org/springframework/integration/cassandra/outbound/package-info.java b/spring-integration-cassandra/src/main/java/org/springframework/integration/cassandra/outbound/package-info.java
index 32acd1b881..4470882581 100644
--- a/spring-integration-cassandra/src/main/java/org/springframework/integration/cassandra/outbound/package-info.java
+++ b/spring-integration-cassandra/src/main/java/org/springframework/integration/cassandra/outbound/package-info.java
@@ -1,5 +1,5 @@
 /**
  * Provides classes supporting Cassandra outbound endpoints.
  */
-@org.springframework.lang.NonNullApi
+@org.jspecify.annotations.NullMarked
 package org.springframework.integration.cassandra.outbound;