Add Nullability support into Java DSL

spring-integration-amqp/src/main/java/org/springframework/integration/amqp/dsl/AbstractMessageListenerContainerSpec.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017-2022 the original author or authors.
+ * Copyright 2017-2023 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.
@@ -290,7 +290,7 @@ public S recoveryBackOff(BackOff recoveryBackOff) {
 
 	/**
 	 * Set the {@link MessagePropertiesConverter} for this listener container.
-	 * @param messagePropertiesConverter The properties converter.
+	 * @param messagePropertiesConverter the converter for AMQP properties.
 	 * @return the spec.
 	 * @see AbstractMessageListenerContainer#setMessagePropertiesConverter(MessagePropertiesConverter)
 	 */

spring-integration-amqp/src/main/java/org/springframework/integration/amqp/dsl/AmqpInboundChannelAdapterDMLCSpec.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017-2020 the original author or authors.
+ * Copyright 2017-2023 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.
@@ -36,7 +36,9 @@ protected AmqpInboundChannelAdapterDMLCSpec(DirectMessageListenerContainer liste
 		super(new DirectMessageListenerContainerSpec(listenerContainer));
 	}
 
-	public AmqpInboundChannelAdapterDMLCSpec configureContainer(Consumer<DirectMessageListenerContainerSpec> configurer) {
+	public AmqpInboundChannelAdapterDMLCSpec configureContainer(
+			Consumer<DirectMessageListenerContainerSpec> configurer) {
+
 		configurer.accept((DirectMessageListenerContainerSpec) this.listenerContainerSpec);
 		return this;
 	}

spring-integration-amqp/src/main/java/org/springframework/integration/amqp/dsl/AmqpInboundChannelAdapterSMLCSpec.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017-2020 the original author or authors.
+ * Copyright 2017-2023 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.
@@ -37,7 +37,9 @@ protected AmqpInboundChannelAdapterSMLCSpec(SimpleMessageListenerContainer liste
 		super(new SimpleMessageListenerContainerSpec(listenerContainer));
 	}
 
-	public AmqpInboundChannelAdapterSMLCSpec configureContainer(Consumer<SimpleMessageListenerContainerSpec> configurer) {
+	public AmqpInboundChannelAdapterSMLCSpec configureContainer(
+			Consumer<SimpleMessageListenerContainerSpec> configurer) {
+
 		configurer.accept((SimpleMessageListenerContainerSpec) this.listenerContainerSpec);
 		return this;
 	}

spring-integration-amqp/src/main/java/org/springframework/integration/amqp/dsl/package-info.java

@@ -1,4 +1,5 @@
 /**
  * Provides AMQP Component support for the Java DSL.
  */
+@org.springframework.lang.NonNullApi
 package org.springframework.integration.amqp.dsl;

spring-integration-cassandra/src/main/java/org/springframework/integration/cassandra/dsl/package-info.java

@@ -1,4 +1,6 @@
 /**
  * Provides Apache Cassandra Components support for the Java DSL.
  */
+@org.springframework.lang.NonNullApi
+@org.springframework.lang.NonNullFields
 package org.springframework.integration.cassandra.dsl;

spring-integration-cassandra/src/main/java/org/springframework/integration/cassandra/outbound/CassandraMessageHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022 the original author or authors.
+ * Copyright 2022-2023 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.
@@ -50,6 +50,7 @@
 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;
 
@@ -75,6 +76,7 @@ public class CassandraMessageHandler extends AbstractReplyProducingMessageHandle
 	/**
 	 * Prepared statement to use in association with high throughput ingestion.
 	 */
+	@Nullable
 	private String ingestQuery;
 
 	/**

spring-integration-cassandra/src/main/java/org/springframework/integration/cassandra/outbound/package-info.java

@@ -1,20 +1,5 @@
-/*
- * Copyright 2022 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.
- * You may obtain a copy of the License at
- *
- *      https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
 /**
  * Provides classes supporting Cassandra outbound endpoints.
  */
+@org.springframework.lang.NonNullApi
 package org.springframework.integration.cassandra.outbound;

spring-integration-core/src/main/java/org/springframework/integration/config/CorrelationStrategyFactoryBean.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -25,6 +25,7 @@
 import org.springframework.integration.aggregator.HeaderAttributeCorrelationStrategy;
 import org.springframework.integration.aggregator.MethodInvokingCorrelationStrategy;
 import org.springframework.integration.util.MessagingAnnotationUtils;
+import org.springframework.lang.NonNull;
 import org.springframework.util.StringUtils;
 
 /**
@@ -75,6 +76,7 @@ public void afterPropertiesSet() {
 		}
 	}
 
+	@NonNull
 	@Override
 	public CorrelationStrategy getObject() {
 		return this.strategy;

spring-integration-core/src/main/java/org/springframework/integration/config/ReleaseStrategyFactoryBean.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -27,6 +27,7 @@
 import org.springframework.integration.aggregator.ReleaseStrategy;
 import org.springframework.integration.aggregator.SimpleSequenceSizeReleaseStrategy;
 import org.springframework.integration.util.MessagingAnnotationUtils;
+import org.springframework.lang.NonNull;
 import org.springframework.util.StringUtils;
 
 /**
@@ -87,6 +88,7 @@ public void afterPropertiesSet() {
 		}
 	}
 
+	@NonNull
 	@Override
 	public ReleaseStrategy getObject() {
 		return this.strategy;

spring-integration-core/src/main/java/org/springframework/integration/context/IntegrationObjectSupport.java

@@ -98,7 +98,7 @@ public abstract class IntegrationObjectSupport implements BeanNameAware, NamedCo
 	private boolean initialized;
 
 	@Override
-	public final void setBeanName(String beanName) {
+	public final void setBeanName(@Nullable String beanName) {
 		this.beanName = beanName;
 	}
 

spring-integration-core/src/main/java/org/springframework/integration/dsl/AggregatorSpec.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2021 the original author or authors.
+ * Copyright 2016-2023 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.
@@ -27,6 +27,7 @@
 import org.springframework.integration.aggregator.MessageGroupProcessor;
 import org.springframework.integration.aggregator.MethodInvokingMessageGroupProcessor;
 import org.springframework.integration.store.MessageGroup;
+import org.springframework.lang.Nullable;
 
 /**
  * A {@link CorrelationHandlerSpec} for an {@link AggregatingMessageHandler}.
@@ -65,7 +66,7 @@ public AggregatorSpec processor(Object target) {
 	 * target object must have an {@link org.springframework.integration.annotation.Aggregator} annotation).
 	 * @return the handler spec.
 	 */
-	public AggregatorSpec processor(Object target, String methodName) {
+	public AggregatorSpec processor(Object target, @Nullable String methodName) {
 		return super.processor(target)
 				.outputProcessor(methodName != null
 						? new MethodInvokingMessageGroupProcessor(target, methodName)