Polish and reinstate usage of FileSystemUtils.deleteRecursively

Closes gh-9942

Author: wilkinsona

spring-boot-integration-tests/spring-boot-devtools-tests/src/test/java/org/springframework/boot/devtools/tests/JarFileRemoteApplicationLauncher.java

@@ -42,12 +42,10 @@ public class JarFileRemoteApplicationLauncher extends RemoteApplicationLauncher
 	@Override
 	protected String createApplicationClassPath() throws Exception {
 		File appDirectory = new File("target/app");
-		if (appDirectory.isDirectory()) {
-			FileSystemUtils.deleteRecursively(appDirectory.toPath());
-			if (appDirectory.isDirectory()) {
-				throw new IllegalStateException(
-						"Failed to delete '" + appDirectory.getAbsolutePath() + "'");
-			}
+		if (appDirectory.isDirectory()
+				&& !FileSystemUtils.deleteRecursively(appDirectory.toPath())) {
+			throw new IllegalStateException(
+					"Failed to delete '" + appDirectory.getAbsolutePath() + "'");
 		}
 		appDirectory.mkdirs();
 		Manifest manifest = new Manifest();

spring-boot-samples/spring-boot-sample-integration/src/test/java/sample/integration/consumer/SampleIntegrationApplicationTests.java

@@ -19,10 +19,6 @@
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
-import java.nio.file.FileVisitOption;
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.util.Comparator;
 import java.util.concurrent.Callable;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
@@ -39,6 +35,7 @@
 import org.springframework.core.io.DefaultResourceLoader;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.support.ResourcePatternUtils;
+import org.springframework.util.FileSystemUtils;
 import org.springframework.util.StreamUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -54,16 +51,14 @@ public class SampleIntegrationApplicationTests {
 	private ConfigurableApplicationContext context;
 
 	@Before
-	public void deleteInputAndOutput() throws InterruptedException, IOException {
+	public void deleteInputAndOutput() throws InterruptedException {
 		deleteIfExists(new File("target/input"));
 		deleteIfExists(new File("target/output"));
 	}
 
-	private void deleteIfExists(File directory) throws InterruptedException, IOException {
+	private void deleteIfExists(File directory) throws InterruptedException {
 		if (directory.exists()) {
-			Files.walk(directory.toPath(), FileVisitOption.FOLLOW_LINKS)
-					.sorted(Comparator.reverseOrder()).map(Path::toFile)
-					.forEach(File::delete);
+			assertThat(FileSystemUtils.deleteRecursively(directory)).isTrue();
 		}
 	}