Merge pull request #27698 from thegeekyasian

* gh-27698:
  Polish "Avoid NPE when routing DataSource has target with null key"
  Avoid NPE when routing DataSource has target with null key

Closes gh-27698

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/jdbc/DataSourceHealthContributorAutoConfiguration.java

@@ -19,6 +19,7 @@ package org.springframework.boot.actuate.autoconfigure.jdbc;
 import java.util.Collection;
 import java.util.Iterator;
 import java.util.Map;
+import java.util.Objects;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
@@ -57,6 +58,7 @@ import org.springframework.util.Assert;
  * @author Stephane Nicoll
  * @author Arthur Kalimullin
  * @author Julio Gomez
+ * @author Safeer Ansari
  * @since 2.0.0
  */
 @Configuration(proxyBeanMethods = false)
@@ -124,10 +126,13 @@ public class DataSourceHealthContributorAutoConfiguration implements Initializin
 
 		private final CompositeHealthContributor delegate;
 
+		private static final String UNNAMED_DATASOURCE_KEY = "unnamed";
+
 		RoutingDataSourceHealthContributor(AbstractRoutingDataSource routingDataSource,
 				Function<DataSource, HealthContributor> contributorFunction) {
 			Map<String, DataSource> routedDataSources = routingDataSource.getResolvedDataSources().entrySet().stream()
-					.collect(Collectors.toMap((e) -> e.getKey().toString(), Map.Entry::getValue));
+					.collect(Collectors.toMap((e) -> Objects.toString(e.getKey(), UNNAMED_DATASOURCE_KEY),
+							Map.Entry::getValue));
 			this.delegate = CompositeHealthContributor.fromMap(routedDataSources, contributorFunction);
 		}
 

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/jdbc/DataSourceHealthContributorAutoConfigurationTests.java

@@ -49,6 +49,7 @@ import static org.mockito.Mockito.mock;
  *
  * @author Phillip Webb
  * @author Julio Gomez
+ * @author Safeer Ansari
  */
 class DataSourceHealthContributorAutoConfigurationTests {
 
@@ -136,6 +137,20 @@ class DataSourceHealthContributorAutoConfigurationTests {
 						.doesNotHaveBean(CompositeHealthContributor.class));
 	}
 
+	@Test
+	void runWhenDataSourceHasNullRoutingKeyShouldProduceUnnamedComposedIndicator() {
+		this.contextRunner.withUserConfiguration(NullKeyRoutingDataSourceConfig.class).run((context) -> {
+			assertThat(context).hasSingleBean(RoutingDataSourceHealthContributor.class);
+			RoutingDataSourceHealthContributor routingHealthContributor = context
+					.getBean(RoutingDataSourceHealthContributor.class);
+			assertThat(routingHealthContributor.getContributor("unnamed"))
+					.isInstanceOf(DataSourceHealthIndicator.class);
+			assertThat(routingHealthContributor.getContributor("one")).isInstanceOf(DataSourceHealthIndicator.class);
+			assertThat(routingHealthContributor.iterator()).toIterable().extracting("name")
+					.containsExactlyInAnyOrder("unnamed", "one");
+		});
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	@EnableConfigurationProperties
 	static class DataSourceConfig {
@@ -164,4 +179,19 @@ class DataSourceHealthContributorAutoConfigurationTests {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	static class NullKeyRoutingDataSourceConfig {
+
+		@Bean
+		AbstractRoutingDataSource routingDataSource() {
+			Map<Object, DataSource> dataSources = new HashMap<>();
+			dataSources.put(null, mock(DataSource.class));
+			dataSources.put("one", mock(DataSource.class));
+			AbstractRoutingDataSource routingDataSource = mock(AbstractRoutingDataSource.class);
+			given(routingDataSource.getResolvedDataSources()).willReturn(dataSources);
+			return routingDataSource;
+		}
+
+	}
+
 }