Merge pull request #16947 from Alan Gomes

* gh-16947:
  Polish "Configure FluentConfiguration to use ResourceLoader's ClassLoader"
  Configure FluentConfiguration to use ResourceLoader's ClassLoader

Closes gh-16947

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/flyway/FlywayAutoConfiguration.java

@@ -113,7 +113,8 @@ public class FlywayAutoConfiguration {
 				ObjectProvider<FlywayConfigurationCustomizer> fluentConfigurationCustomizers,
 				ObjectProvider<Callback> callbacks,
 				ObjectProvider<FlywayCallback> flywayCallbacks) {
-			FluentConfiguration configuration = new FluentConfiguration();
+			FluentConfiguration configuration = new FluentConfiguration(
+					resourceLoader.getClassLoader());
 			DataSource dataSourceToMigrate = configureDataSource(configuration,
 					properties, dataSourceProperties, flywayDataSource.getIfAvailable(),
 					dataSource.getIfAvailable());

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/flyway/FlywayAutoConfigurationTests.java

@@ -48,6 +48,8 @@ import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Primary;
 import org.springframework.core.Ordered;
 import org.springframework.core.annotation.Order;
+import org.springframework.core.io.DefaultResourceLoader;
+import org.springframework.core.io.ResourceLoader;
 import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
 import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
 import org.springframework.stereotype.Component;
@@ -470,6 +472,17 @@ public class FlywayAutoConfigurationTests {
 				});
 	}
 
+	@Test
+	public void customFlywayClassLoader() {
+		this.contextRunner.withUserConfiguration(EmbeddedDataSourceConfiguration.class,
+				ResourceLoaderConfiguration.class).run((context) -> {
+					assertThat(context).hasSingleBean(Flyway.class);
+					Flyway flyway = context.getBean(Flyway.class);
+					assertThat(flyway.getConfiguration().getClassLoader())
+							.isInstanceOf(CustomClassLoader.class);
+				});
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	protected static class FlywayDataSourceConfiguration {
 
@@ -489,6 +502,18 @@ public class FlywayAutoConfigurationTests {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	protected static class ResourceLoaderConfiguration {
+
+		@Bean
+		@Primary
+		public ResourceLoader customClassLoader() {
+			return new DefaultResourceLoader(
+					new CustomClassLoader(getClass().getClassLoader()));
+		}
+
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	protected static class CustomFlywayMigrationInitializer {
 
@@ -604,4 +629,12 @@ public class FlywayAutoConfigurationTests {
 
 	}
 
+	private static final class CustomClassLoader extends ClassLoader {
+
+		private CustomClassLoader(ClassLoader parent) {
+			super(parent);
+		}
+
+	}
+
 }