GH-1827: Fix New Sonar Issues

Author: garyrussell

spring-kafka/src/main/java/org/springframework/kafka/annotation/KafkaListener.java

@@ -23,7 +23,6 @@
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
-import org.springframework.kafka.listener.ContainerGroup;
 import org.springframework.messaging.handler.annotation.MessageMapping;
 
 /**
@@ -154,7 +153,8 @@
 	 * allows, for example, iteration over the collection to start/stop a subset of
 	 * containers. The {@code Collection} beans are deprecated as of version 2.7.3 and
 	 * will be removed in 2.8. Instead, a bean with name {@code containerGroup + ".group"}
-	 * and type {@link ContainerGroup} should be used instead.
+	 * and type {@link org.springframework.kafka.listener.ContainerGroup} should be used
+	 * instead.
 	 * <p>
 	 * SpEL {@code #{...}} and property place holders {@code ${...}} are supported.
 	 * @return the bean name for the group.

spring-kafka/src/main/java/org/springframework/kafka/listener/ContainerGroupSequencer.java

@@ -94,7 +94,7 @@ public void setApplicationContext(ApplicationContext applicationContext) throws
 	 * default, the containers in the final group remain running.
 	 * @param stopLastGroupWhenIdle true to stop containers in the final group.
 	 */
-	public void setStopLastGroupWhenIdle(boolean stopLastGroupWhenIdle) {
+	public synchronized void setStopLastGroupWhenIdle(boolean stopLastGroupWhenIdle) {
 		this.stopLastGroupWhenIdle = stopLastGroupWhenIdle;
 	}
 
@@ -103,21 +103,18 @@ public synchronized void onApplicationEvent(ListenerContainerIdleEvent event) {
 		LOGGER.debug(() -> event.toString());
 		MessageListenerContainer parent = event.getContainer(MessageListenerContainer.class);
 		MessageListenerContainer container = (MessageListenerContainer) event.getSource();
-		if (this.running) {
-			if (this.currentGroup != null && this.currentGroup.contains(parent)) {
-				if (this.iterator.hasNext() || this.stopLastGroupWhenIdle) {
-					this.executor.execute(() -> {
-						LOGGER.debug(() -> "Stopping: " + container);
-						container.stop(() -> {
-							if (!parent.isChildRunning()) {
-								this.executor.execute(() -> {
-									stopParentAndCheckGroup(parent);
-								});
-							}
+		boolean inCurrentGroup = this.currentGroup != null && this.currentGroup.contains(parent);
+		if (this.running && inCurrentGroup && (this.iterator.hasNext() || this.stopLastGroupWhenIdle)) {
+			this.executor.execute(() -> {
+				LOGGER.debug(() -> "Stopping: " + container);
+				container.stop(() -> {
+					if (!parent.isChildRunning()) {
+						this.executor.execute(() -> {
+							stopParentAndCheckGroup(parent);
 						});
-					});
-				}
-			}
+					}
+				});
+			});
 		}
 	}
 

spring-kafka/src/main/java/org/springframework/kafka/listener/ContainerProperties.java

@@ -459,6 +459,7 @@ public long getShutdownTimeout() {
 		return this.shutdownTimeout;
 	}
 
+	@Nullable
 	public Long getIdleEventInterval() {
 		return this.idleEventInterval;
 	}

spring-kafka/src/main/java/org/springframework/kafka/listener/KafkaMessageListenerContainer.java

@@ -1506,10 +1506,11 @@ private void resumePartitionsIfNecessary() {
 		}
 
 		private void checkIdle() {
-			if (this.containerProperties.getIdleEventInterval() != null) {
+			Long idleEventInterval = this.containerProperties.getIdleEventInterval();
+			if (idleEventInterval != null) {
 				long now = System.currentTimeMillis();
-				if (now > this.lastReceive + this.containerProperties.getIdleEventInterval()
-						&& now > this.lastAlertAt + this.containerProperties.getIdleEventInterval()) {
+				if (now > this.lastReceive + idleEventInterval
+						&& now > this.lastAlertAt + idleEventInterval) {
 					this.wasIdle = true;
 					publishIdleContainerEvent(now - this.lastReceive, this.consumer, this.consumerPaused);
 					this.lastAlertAt = now;