Respect executor set on container props

Makes sure that the ConcurrentPulsarListenerContainerFactory copies the
task executor from the factory container properties to the container
instance properties.

Backports the fix for #1103 from 6dcc813576.

The change was manually applied as the concurrent unit test class diverged heavily.

See #1103

Signed-off-by: Daniel Szabo <cheery.gate6737@milkmail.eu>

spring-pulsar/src/main/java/org/springframework/pulsar/config/ConcurrentPulsarListenerContainerFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022-2023 the original author or authors.
+ * Copyright 2022-2025 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.
@@ -33,6 +33,7 @@ import org.springframework.util.StringUtils;
  * @author Soby Chacko
  * @author Chris Bono
  * @author Alexander Preuß
+ * @author Daniel Szabo
  */
 public class ConcurrentPulsarListenerContainerFactory<T>
 		extends AbstractPulsarListenerContainerFactory<ConcurrentPulsarMessageListenerContainer<T>, T> {
@@ -74,6 +75,7 @@ public class ConcurrentPulsarListenerContainerFactory<T>
 		PulsarContainerProperties properties = new PulsarContainerProperties();
 		properties.setSchemaResolver(this.getContainerProperties().getSchemaResolver());
 		properties.setTopicResolver(this.getContainerProperties().getTopicResolver());
+		properties.setConsumerTaskExecutor(this.getContainerProperties().getConsumerTaskExecutor());
 
 		var parentTxnProps = this.getContainerProperties().transactions();
 		var childTxnProps = properties.transactions();

spring-pulsar/src/test/java/org/springframework/pulsar/config/ConcurrentPulsarListenerContainerFactoryTests.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2025-2025 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.
+ * 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.
+ */
+
+package org.springframework.pulsar.config;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.core.task.AsyncTaskExecutor;
+import org.springframework.pulsar.core.PulsarConsumerFactory;
+import org.springframework.pulsar.listener.PulsarContainerProperties;
+
+/**
+ * Unit tests for {@link ConcurrentPulsarListenerContainerFactory}.
+ *
+ * @author Daniel Szabo
+ * @author Chris Bono
+ */
+class ConcurrentPulsarListenerContainerFactoryTests {
+
+	@Nested
+	class ConsumerTaskExecutorFrom {
+
+		@Test
+		@SuppressWarnings("unchecked")
+		void factoryPropsUsedWhenSpecified() {
+			var factoryProps = new PulsarContainerProperties();
+			AsyncTaskExecutor executor = mock();
+			factoryProps.setConsumerTaskExecutor(executor);
+			var containerFactory = new ConcurrentPulsarListenerContainerFactory<String>(
+					mock(PulsarConsumerFactory.class), factoryProps);
+			var endpoint = mock(PulsarListenerEndpoint.class);
+			when(endpoint.getConcurrency()).thenReturn(1);
+
+			var container = containerFactory.createContainerInstance(endpoint);
+			assertThat(container.getContainerProperties())
+				.extracting(PulsarContainerProperties::getConsumerTaskExecutor)
+				.isSameAs(executor);
+		}
+
+	}
+
+}