Merge pull request #48484 from youngledo

* pr/48484:
  Polish "Use 'unknown' when RabbitMQ version is missing"
  Use 'unknown' when RabbitMQ version is missing

Closes gh-48484

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/amqp/RabbitHealthIndicator.java

@@ -45,8 +45,10 @@ public class RabbitHealthIndicator extends AbstractHealthIndicator {
 	}
 
 	private String getVersion() {
-		return this.rabbitTemplate
-			.execute((channel) -> channel.getConnection().getServerProperties().get("version").toString());
+		return this.rabbitTemplate.execute((channel) -> channel.getConnection()
+			.getServerProperties()
+			.getOrDefault("version", "unknown")
+			.toString());
 	}
 
 }

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/amqp/RabbitHealthIndicatorTests.java

@@ -67,6 +67,17 @@ class RabbitHealthIndicatorTests {
 		assertThat(health.getDetails()).containsEntry("version", "123");
 	}
 
+	@Test
+	void healthWhenVersionIsMissingShouldReturnUpWithUnknownVersion() {
+		givenTemplateExecutionWillInvokeCallback();
+		Connection connection = mock(Connection.class);
+		given(this.channel.getConnection()).willReturn(connection);
+		given(connection.getServerProperties()).willReturn(Collections.emptyMap());
+		Health health = new RabbitHealthIndicator(this.rabbitTemplate).health();
+		assertThat(health.getStatus()).isEqualTo(Status.UP);
+		assertThat(health.getDetails()).containsEntry("version", "unknown");
+	}
+
 	@Test
 	void healthWhenConnectionFailsShouldReturnDown() {
 		givenTemplateExecutionWillInvokeCallback();