Merge branch '2.3.x'

Closes gh-24200

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/jdbc/DataSourceUnwrapper.java

 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -74,7 +74,7 @@ public final class DataSourceUnwrapper {
 
 	private static <S> S safeUnwrap(Wrapper wrapper, Class<S> target) {
 		try {
-			if (wrapper.isWrapperFor(target)) {
+			if (target.isInterface() && wrapper.isWrapperFor(target)) {
 				return wrapper.unwrap(target);
 			}
 		}

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/jdbc/DataSourceUnwrapperTests.java

 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -17,6 +17,7 @@
 package org.springframework.boot.jdbc;
 
 import java.sql.SQLException;
+import java.util.function.Consumer;
 
 import javax.sql.DataSource;
 
@@ -87,12 +88,18 @@ class DataSourceUnwrapperTests {
 		assertThat(DataSourceUnwrapper.unwrap(actual, DataSourceProxy.class)).isSameAs(dataSource);
 	}
 
+	@Test
+	void unwrappingIsNotAttemptedWhenTargetIsNotAnInterface() throws SQLException {
+		DataSource dataSource = mock(DataSource.class);
+		assertThat(DataSourceUnwrapper.unwrap(dataSource, HikariDataSource.class)).isNull();
+		verifyNoMoreInteractions(dataSource);
+	}
+
 	@Test
 	void unwrappingIsNotAttemptedWhenDataSourceIsNotWrapperForTarget() throws SQLException {
 		DataSource dataSource = mock(DataSource.class);
-		DataSource actual = DataSourceUnwrapper.unwrap(dataSource, HikariDataSource.class);
-		assertThat(actual).isNull();
-		verify(dataSource).isWrapperFor(HikariDataSource.class);
+		assertThat(DataSourceUnwrapper.unwrap(dataSource, Consumer.class)).isNull();
+		verify(dataSource).isWrapperFor(Consumer.class);
 		verifyNoMoreInteractions(dataSource);
 	}