GH-10083: Add NullAway core package

* GH-10083: Add NullAway core package

- Add explicit Consumer cast in AggregatorFactoryBean for lockRegistry
   method reference to resolve type parameter nullability mismatch
- Complete nullability annotation migration for core integration package

* GH-10083: Fix @nullable annotation placement in IntegrationMessageHeaderAccessor

Author: cppwfs

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

@@ -114,13 +114,11 @@ public void setReadOnlyHeaders(String... readOnlyHeaders) {
 		}
 	}
 
-	@Nullable
-	public Long getExpirationDate() {
+	public @Nullable Long getExpirationDate() {
 		return getHeader(EXPIRATION_DATE, Long.class);
 	}
 
-	@Nullable
-	public Object getCorrelationId() {
+	public @Nullable Object getCorrelationId() {
 		return getHeader(CORRELATION_ID);
 	}
 
@@ -134,8 +132,7 @@ public int getSequenceSize() {
 		return (sequenceSize != null ? sequenceSize.intValue() : 0);
 	}
 
-	@Nullable
-	public Integer getPriority() {
+	public @Nullable Integer getPriority() {
 		Number priority = getHeader(PRIORITY, Number.class);
 		return (priority != null ? priority.intValue() : null);
 	}
@@ -149,8 +146,7 @@ public Integer getPriority() {
 	 * @return the {@link Closeable}.
 	 * @since 4.3
 	 */
-	@Nullable
-	public Closeable getCloseableResource() {
+	public @Nullable Closeable getCloseableResource() {
 		return getHeader(CLOSEABLE_RESOURCE, Closeable.class);
 	}
 
@@ -159,8 +155,7 @@ public Closeable getCloseableResource() {
 	 * @return the callback.
 	 * @since 5.0.1
 	 */
-	@Nullable
-	public AcknowledgmentCallback getAcknowledgmentCallback() {
+	public @Nullable AcknowledgmentCallback getAcknowledgmentCallback() {
 		return getHeader(ACKNOWLEDGMENT_CALLBACK, AcknowledgmentCallback.class);
 	}
 
@@ -170,8 +165,7 @@ public AcknowledgmentCallback getAcknowledgmentCallback() {
 	 * @return the delivery attempt.
 	 * @since 5.0.1
 	 */
-	@Nullable
-	public AtomicInteger getDeliveryAttempt() {
+	public @Nullable AtomicInteger getDeliveryAttempt() {
 		return getHeader(DELIVERY_ATTEMPT, AtomicInteger.class);
 	}
 
@@ -182,8 +176,7 @@ public AtomicInteger getDeliveryAttempt() {
 	 * @since 5.1.6
 	 */
 	@SuppressWarnings("unchecked")
-	@Nullable
-	public <T> T getSourceData() {
+	public <T>  @Nullable T getSourceData() {
 		return (T) getHeader(SOURCE_DATA);
 	}
 
@@ -192,14 +185,12 @@ public <T> T getSourceData() {
 	 * @return the {@link ContextView} header if present.
 	 * @since 6.0.5
 	 */
-	@Nullable
-	public ContextView getReactorContext() {
+	public @Nullable ContextView getReactorContext() {
 		return getHeader(REACTOR_CONTEXT, ContextView.class);
 	}
 
 	@SuppressWarnings("unchecked")
-	@Nullable
-	public <T> T getHeader(String key, Class<T> type) {
+	public <T> @Nullable T getHeader(String key, Class<T> type) {
 		Object value = getHeader(key);
 		if (value == null) {
 			return null;
@@ -212,7 +203,7 @@ public <T> T getHeader(String key, Class<T> type) {
 	}
 
 	@Override
-	protected void verifyType(String headerName, Object headerValue) {
+	protected void verifyType(@Nullable String headerName, @Nullable Object headerValue) {
 		if (headerName != null && headerValue != null) {
 			super.verifyType(headerName, headerValue);
 			if (IntegrationMessageHeaderAccessor.EXPIRATION_DATE.equals(headerName)) {

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

@@ -20,6 +20,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.function.BiFunction;
+import java.util.function.Consumer;
 import java.util.function.Function;
 
 import org.aopalliance.aop.Advice;
@@ -238,7 +239,7 @@ protected AggregatingMessageHandler createHandler() {
 				.acceptIfNotNull(this.expireGroupsUponCompletion, aggregator::setExpireGroupsUponCompletion)
 				.acceptIfNotNull(this.sendTimeout, aggregator::setSendTimeout)
 				.acceptIfNotNull(this.outputChannelName, aggregator::setOutputChannelName)
-				.acceptIfNotNull(this.lockRegistry, aggregator::setLockRegistry)
+				.acceptIfNotNull(this.lockRegistry, (Consumer<LockRegistry<?>>) aggregator::setLockRegistry)
 				.acceptIfNotNull(this.messageStore, aggregator::setMessageStore)
 				.acceptIfNotNull(obtainCorrelationStrategy(), aggregator::setCorrelationStrategy)
 				.acceptIfNotNull(obtainReleaseStrategy(), aggregator::setReleaseStrategy)

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

@@ -3,5 +3,5 @@
  *
  * Provides fundamental classes.
  */
-@org.springframework.lang.NonNullApi
+@org.jspecify.annotations.NullMarked
 package org.springframework.integration;