RabbitMQ AMQP 1.0 should not set an empty exchange by default

module/spring-boot-amqp-rabbitmq/src/main/java/org/springframework/boot/amqp/rabbitmq/autoconfigure/AmqpRabbitProperties.java

@@ -295,32 +295,32 @@ public static class Template {
 		/**
 		 * Name of the default exchange to use for send operations.
 		 */
-		private String exchange = "";
+		private @Nullable String exchange;
 
 		/**
 		 * Value of a default routing key to use for send operations.
 		 */
-		private String routingKey = "";
+		private @Nullable String routingKey;
 
 		/**
 		 * Name of the default queue to receive messages from when none is specified
 		 * explicitly.
 		 */
 		private @Nullable String defaultReceiveQueue;
 
-		public String getExchange() {
+		public @Nullable String getExchange() {
 			return this.exchange;
 		}
 
-		public void setExchange(String exchange) {
+		public void setExchange(@Nullable String exchange) {
 			this.exchange = exchange;
 		}
 
-		public String getRoutingKey() {
+		public @Nullable String getRoutingKey() {
 			return this.routingKey;
 		}
 
-		public void setRoutingKey(String routingKey) {
+		public void setRoutingKey(@Nullable String routingKey) {
 			this.routingKey = routingKey;
 		}
 

module/spring-boot-amqp-rabbitmq/src/test/java/org/springframework/boot/amqp/rabbitmq/autoconfigure/AmqpRabbitAutoConfigurationTests.java

@@ -219,6 +219,18 @@ void autoConfigurationConfiguresRabbitAmqpTemplateWithTemplateProperties() {
 			});
 	}
 
+	@Test
+	void autoConfigurationDoesNotConfigureRabbitAmqpTemplateExchangeAndRoutingKeyByDefault() {
+		this.contextRunner
+			.withBean(RabbitAmqpTemplateCustomizer.class, () -> (template) -> template.setQueue("test.queue"))
+			.run((context) -> {
+				RabbitAmqpTemplate template = context.getBean(RabbitAmqpTemplate.class);
+				assertThat(template).hasFieldOrPropertyWithValue("defaultQueue", "test.queue");
+				assertThat(template).hasFieldOrPropertyWithValue("defaultExchange", null);
+				assertThat(template).hasFieldOrPropertyWithValue("defaultRoutingKey", null);
+			});
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	static class MultipleRabbitAmqpTemplateCustomizersConfiguration {