jspecify nullability changes for the streams package

Signed-off-by: Soby Chacko <[email protected]>

Author: sobychacko

Diff for: spring-kafka/src/main/java/org/springframework/kafka/streams/HeaderEnricherProcessor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2023 the original author or authors.
+ * Copyright 2019-2025 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.
@@ -60,7 +60,12 @@ public void process(Record<K, V> record) {
 				headerValue = ((String) headerValue).getBytes(StandardCharsets.UTF_8);
 			}
 			else if (!(headerValue instanceof byte[])) {
-				throw new IllegalStateException("Invalid header value type: " + headerValue.getClass());
+				if (headerValue != null) {
+					throw new IllegalStateException("Invalid header value type: " + headerValue.getClass());
+				}
+				else {
+					throw new IllegalStateException("headerValue is null");
+				}
 			}
 			headers.add(new RecordHeader(name, (byte[]) headerValue));
 		});

Diff for: spring-kafka/src/main/java/org/springframework/kafka/streams/KafkaStreamsInteractiveQueryService.java

@@ -54,7 +54,7 @@ public class KafkaStreamsInteractiveQueryService {
 	/**
 	 * Underlying {@link KafkaStreams} from {@link StreamsBuilderFactoryBean}.
 	 */
-	private volatile KafkaStreams kafkaStreams;
+	private volatile @Nullable KafkaStreams kafkaStreams;
 
 	/**
 	 * Construct an instance for querying state stores from the KafkaStreams in the {@link StreamsBuilderFactoryBean}.
@@ -87,6 +87,7 @@ public <T> T retrieveQueryableStore(String storeName, QueryableStoreType<T> stor
 
 		return this.retryTemplate.execute(context -> {
 			try {
+				Assert.state(this.kafkaStreams != null, "KafkaStreams cannot be null.");
 				return this.kafkaStreams.store(storeQueryParams);
 			}
 			catch (Exception e) {
@@ -143,6 +144,7 @@ public <K> HostInfo getKafkaStreamsApplicationHostInfo(String store, K key, Seri
 		return this.retryTemplate.execute(context -> {
 			Throwable throwable = null;
 			try {
+				Assert.state(this.kafkaStreams != null, "KafkaStreams cannot be null.");
 				KeyQueryMetadata keyQueryMetadata = this.kafkaStreams.queryMetadataForKey(store, key, serializer);
 				if (keyQueryMetadata != null) {
 					return keyQueryMetadata.activeHost();

Diff for: spring-kafka/src/main/java/org/springframework/kafka/streams/RecoveringDeserializationExceptionHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2019 the original author or authors.
+ * Copyright 2019-2025 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.
@@ -24,6 +24,7 @@
 import org.apache.kafka.clients.consumer.ConsumerRecord;
 import org.apache.kafka.streams.errors.DeserializationExceptionHandler;
 import org.apache.kafka.streams.processor.ProcessorContext;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.kafka.listener.ConsumerRecordRecoverer;
 import org.springframework.util.ClassUtils;
@@ -45,7 +46,7 @@ public class RecoveringDeserializationExceptionHandler implements Deserializatio
 
 	private static final Log LOGGER = LogFactory.getLog(RecoveringDeserializationExceptionHandler.class);
 
-	private ConsumerRecordRecoverer recoverer;
+	private @Nullable ConsumerRecordRecoverer recoverer;
 
 	public RecoveringDeserializationExceptionHandler() {
 	}

Diff for: spring-kafka/src/main/java/org/springframework/kafka/streams/messaging/MessagingProcessor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2022 the original author or authors.
+ * Copyright 2019-2025 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.
@@ -84,7 +84,7 @@ public void process(Record<Kin, Vin> record) {
 		message = this.function.exchange(message);
 		List<String> headerList = new ArrayList<>();
 		headers.forEach(header -> headerList.add(header.key()));
-		headerList.forEach(name -> headers.remove(name));
+		headerList.forEach(headers::remove);
 		ProducerRecord<?, ?> fromMessage = this.converter.fromMessage(message, "dummy");
 		fromMessage.headers().forEach(header -> {
 			if (!header.key().equals(KafkaHeaders.TOPIC)) {

Diff for: spring-kafka/src/main/java/org/springframework/kafka/streams/messaging/package-info.java

@@ -1,4 +1,5 @@
 /**
  * Package for classes related to spring-messaging with Kafka Streams.
  */
+@org.jspecify.annotations.NullMarked
 package org.springframework.kafka.streams.messaging;

Diff for: spring-kafka/src/main/java/org/springframework/kafka/streams/package-info.java

@@ -1,4 +1,5 @@
 /**
  * Package for classes related to Kafka Streams.
  */
+@org.jspecify.annotations.NullMarked
 package org.springframework.kafka.streams;