diff --git a/gradle/spring-module.gradle b/gradle/spring-module.gradle
index fa8ef8cf672c..8681e4a8889b 100644
--- a/gradle/spring-module.gradle
+++ b/gradle/spring-module.gradle
@@ -118,7 +118,7 @@ tasks.withType(JavaCompile).configureEach {
     	disableAllChecks = true
         option("NullAway:CustomContractAnnotations", "org.springframework.lang.Contract")
         option("NullAway:AnnotatedPackages", "org.springframework.core,org.springframework.expression," +
-        		"org.springframework.web,org.springframework.jms")
+        		"org.springframework.web,org.springframework.jms,org.springframework.messaging")
         option("NullAway:UnannotatedSubPackages", "org.springframework.instrument,org.springframework.context.index," +
 				"org.springframework.asm,org.springframework.cglib,org.springframework.objenesis," +
 				"org.springframework.javapoet,org.springframework.aot.nativex.substitution")
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/handler/HandlerMethod.java b/spring-messaging/src/main/java/org/springframework/messaging/handler/HandlerMethod.java
index c12f8d6c0c07..5b1e37b08a91 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/handler/HandlerMethod.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/handler/HandlerMethod.java
@@ -196,7 +196,8 @@ public String getShortLogMessage() {
 
 	@Override
 	public boolean equals(@Nullable Object other) {
-		return (this == other || (super.equals(other) && this.bean.equals(((HandlerMethod) other).bean)));
+		return (this == other || (super.equals(other) && other instanceof HandlerMethod otherMethod
+				&& this.bean.equals(otherMethod.bean)));
 	}
 
 	@Override
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/reactive/MessageMappingMessageHandler.java b/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/reactive/MessageMappingMessageHandler.java
index c4872d1825f0..571ef653b357 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/reactive/MessageMappingMessageHandler.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/reactive/MessageMappingMessageHandler.java
@@ -305,6 +305,7 @@ protected CompositeMessageCondition getCondition(AnnotatedElement element) {
 	 * @param destinations the destinations
 	 * @return new array with the processed destinations or the same array
 	 */
+	@SuppressWarnings("NullAway")
 	protected String[] processDestinations(String[] destinations) {
 		if (this.valueResolver != null) {
 			destinations = Arrays.stream(destinations)
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/AbstractMethodMessageHandler.java b/spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/AbstractMethodMessageHandler.java
index b6405818912c..6b99dc410cc2 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/AbstractMethodMessageHandler.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/AbstractMethodMessageHandler.java
@@ -522,6 +522,7 @@ protected void handleMessageInternal(Message<?> message, String lookupDestinatio
 		handleMatch(bestMatch.mapping, bestMatch.handlerMethod, lookupDestination, message);
 	}
 
+	@SuppressWarnings("NullAway")
 	private void addMatchesToCollection(Collection<T> mappingsToCheck, Message<?> message, List<Match> matches) {
 		for (T mapping : mappingsToCheck) {
 			T match = getMatchingMapping(mapping, message);
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/reactive/AbstractMethodMessageHandler.java b/spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/reactive/AbstractMethodMessageHandler.java
index 6677c252c9ca..e6e182b6f4c2 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/reactive/AbstractMethodMessageHandler.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/reactive/AbstractMethodMessageHandler.java
@@ -505,6 +505,7 @@ private Match<T> getHandlerMethod(Message<?> message) {
 	@Nullable
 	protected abstract RouteMatcher.Route getDestination(Message<?> message);
 
+	@SuppressWarnings("NullAway")
 	private void addMatchesToCollection(
 			Collection<T> mappingsToCheck, Message<?> message, List<Match<T>> matches) {
 
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompDecoder.java b/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompDecoder.java
index 16fbe5dd8f67..442c4301acc4 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompDecoder.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompDecoder.java
@@ -130,6 +130,7 @@ public List<Message<byte[]>> decode(ByteBuffer byteBuffer,
 	 * Decode a single STOMP frame from the given {@code byteBuffer} into a {@link Message}.
 	 */
 	@Nullable
+	@SuppressWarnings("NullAway")
 	private Message<byte[]> decodeMessage(ByteBuffer byteBuffer, @Nullable MultiValueMap<String, String> headers) {
 		Message<byte[]> decodedMessage = null;
 		skipEol(byteBuffer);
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaderAccessor.java b/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaderAccessor.java
index 846ee4e3777d..799364ccafa9 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaderAccessor.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaderAccessor.java
@@ -237,6 +237,7 @@ public boolean isHeartbeat() {
 		return (SimpMessageType.HEARTBEAT == getMessageType());
 	}
 
+	@SuppressWarnings("NullAway")
 	public long[] getHeartbeat() {
 		String rawValue = getFirstNativeHeader(STOMP_HEARTBEAT_HEADER);
 		int pos = (rawValue != null ? rawValue.indexOf(',') : -1);
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaders.java b/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaders.java
index 381029c3711e..ef253caa5745 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaders.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaders.java
@@ -278,6 +278,7 @@ public void setHeartbeat(@Nullable long[] heartbeat) {
 	 * Get the heartbeat header.
 	 */
 	@Nullable
+	@SuppressWarnings("NullAway")
 	public long[] getHeartbeat() {
 		String rawValue = getFirst(HEARTBEAT);
 		int pos = (rawValue != null ? rawValue.indexOf(',') : -1);
@@ -514,6 +515,7 @@ public boolean containsValue(Object value) {
 	}
 
 	@Override
+	@Nullable
 	public List<String> get(Object key) {
 		return this.headers.get(key);
 	}
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/support/MessageHeaderAccessor.java b/spring-messaging/src/main/java/org/springframework/messaging/support/MessageHeaderAccessor.java
index d452456acab3..317794dbb136 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/support/MessageHeaderAccessor.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/support/MessageHeaderAccessor.java
@@ -645,6 +645,7 @@ public Map<String, Object> getRawHeaders() {
 			return super.getRawHeaders();
 		}
 
+		@SuppressWarnings("NullAway")
 		public void setImmutable() {
 			if (!this.mutable) {
 				return;