Merge branch '4.0.x'

Closes gh-48701

module/spring-boot-devtools/src/intTest/java/com/example/package-info.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2012-present 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+@NullMarked
+package com.example;
+
+import org.jspecify.annotations.NullMarked;

module/spring-boot-devtools/src/intTest/java/org/springframework/boot/devtools/tests/AbstractDevToolsIntegrationTests.java

@@ -27,11 +27,13 @@ import net.bytebuddy.description.modifier.Visibility;
 import net.bytebuddy.dynamic.DynamicType;
 import net.bytebuddy.implementation.FixedValue;
 import org.awaitility.Awaitility;
+import org.jspecify.annotations.Nullable;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.extension.RegisterExtension;
 import org.junit.jupiter.api.io.TempDir;
 
 import org.springframework.boot.testsupport.BuildOutput;
+import org.springframework.util.Assert;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
@@ -50,32 +52,39 @@ abstract class AbstractDevToolsIntegrationTests {
 	protected final JvmLauncher javaLauncher = new JvmLauncher();
 
 	@TempDir
+	@SuppressWarnings("NullAway.Init")
 	protected static File temp;
 
-	protected LaunchedApplication launchedApplication;
+	private @Nullable LaunchedApplication launchedApplication;
 
-	protected void launchApplication(ApplicationLauncher applicationLauncher, String... args) throws Exception {
+	protected LaunchedApplication launchApplication(ApplicationLauncher applicationLauncher, String... args)
+			throws Exception {
 		this.serverPortFile.delete();
 		this.launchedApplication = applicationLauncher.launchApplication(this.javaLauncher, this.serverPortFile, args);
+		return this.launchedApplication;
 	}
 
 	@AfterEach
 	void stopApplication() throws InterruptedException {
+		Assert.notNull(this.launchedApplication, "Application has not been launched");
 		this.launchedApplication.stop();
 	}
 
 	protected int awaitServerPort() throws Exception {
+		LaunchedApplication launchedApplication = this.launchedApplication;
+		Assert.notNull(launchedApplication, "Application has not been launched");
 		int port = Awaitility.waitAtMost(Duration.ofMinutes(3))
-			.until(() -> new ApplicationState(this.serverPortFile, this.launchedApplication),
+			.until(() -> new ApplicationState(this.serverPortFile, launchedApplication),
 					ApplicationState::hasServerPort)
 			.getServerPort();
 		this.serverPortFile.delete();
-		this.launchedApplication.restartRemote(port);
+		launchedApplication.restartRemote(port);
 		Thread.sleep(1000);
 		return port;
 	}
 
 	protected ControllerBuilder controller(String name) {
+		Assert.notNull(this.launchedApplication, "Application has not been launched");
 		return new ControllerBuilder(name, this.launchedApplication.getClassesDirectory());
 	}
 

module/spring-boot-devtools/src/intTest/java/org/springframework/boot/devtools/tests/ApplicationState.java

@@ -19,7 +19,10 @@ package org.springframework.boot.devtools.tests;
 import java.io.File;
 import java.time.Instant;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.boot.devtools.tests.JvmLauncher.LaunchedJvm;
+import org.springframework.util.Assert;
 
 /**
  * State of an application.
@@ -30,7 +33,7 @@ final class ApplicationState {
 
 	private final Instant launchTime;
 
-	private final Integer serverPort;
+	private final @Nullable Integer serverPort;
 
 	private final FileContents out;
 
@@ -56,6 +59,7 @@ final class ApplicationState {
 	}
 
 	int getServerPort() {
+		Assert.notNull(this.serverPort, "No server port is available");
 		return this.serverPort;
 	}
 

module/spring-boot-devtools/src/intTest/java/org/springframework/boot/devtools/tests/DevToolsIntegrationTests.java

@@ -125,10 +125,10 @@ class DevToolsIntegrationTests extends AbstractDevToolsIntegrationTests {
 	@ParameterizedTest(name = "{0}")
 	@MethodSource("parameters")
 	void deleteAController(ApplicationLauncher applicationLauncher) throws Exception {
-		launchApplication(applicationLauncher);
+		LaunchedApplication launchedApplication = launchApplication(applicationLauncher);
 		String urlBase = "http://localhost:" + awaitServerPort();
 		assertThat(this.template.getForObject(urlBase + "/one", String.class)).isEqualTo("one");
-		assertThat(new File(this.launchedApplication.getClassesDirectory(), "com/example/ControllerOne.class").delete())
+		assertThat(new File(launchedApplication.getClassesDirectory(), "com/example/ControllerOne.class").delete())
 			.isTrue();
 		urlBase = "http://localhost:" + awaitServerPort();
 		assertThat(this.template.getForEntity(urlBase + "/one", String.class).getStatusCode())
@@ -139,7 +139,7 @@ class DevToolsIntegrationTests extends AbstractDevToolsIntegrationTests {
 	@ParameterizedTest(name = "{0}")
 	@MethodSource("parameters")
 	void createAControllerAndThenDeleteIt(ApplicationLauncher applicationLauncher) throws Exception {
-		launchApplication(applicationLauncher);
+		LaunchedApplication launchedApplication = launchApplication(applicationLauncher);
 		String urlBase = "http://localhost:" + awaitServerPort();
 		assertThat(this.template.getForObject(urlBase + "/one", String.class)).isEqualTo("one");
 		assertThat(this.template.getForEntity(urlBase + "/two", String.class).getStatusCode())
@@ -148,7 +148,7 @@ class DevToolsIntegrationTests extends AbstractDevToolsIntegrationTests {
 		urlBase = "http://localhost:" + awaitServerPort();
 		assertThat(this.template.getForObject(urlBase + "/one", String.class)).isEqualTo("one");
 		assertThat(this.template.getForObject(urlBase + "/two", String.class)).isEqualTo("two");
-		assertThat(new File(this.launchedApplication.getClassesDirectory(), "com/example/ControllerTwo.class").delete())
+		assertThat(new File(launchedApplication.getClassesDirectory(), "com/example/ControllerTwo.class").delete())
 			.isTrue();
 		urlBase = "http://localhost:" + awaitServerPort();
 		assertThat(this.template.getForEntity(urlBase + "/two", String.class).getStatusCode())

module/spring-boot-devtools/src/intTest/java/org/springframework/boot/devtools/tests/FileContents.java

@@ -21,6 +21,8 @@ import java.io.FileReader;
 import java.io.IOException;
 import java.util.function.Function;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.util.FileCopyUtils;
 
 /**
@@ -36,11 +38,11 @@ class FileContents {
 		this.file = file;
 	}
 
-	String get() {
+	@Nullable String get() {
 		return get(Function.identity());
 	}
 
-	<T> T get(Function<String, T> transformer) {
+	<T> @Nullable T get(Function<String, T> transformer) {
 		if ((!this.file.exists()) || this.file.length() == 0) {
 			return null;
 		}
@@ -53,7 +55,7 @@ class FileContents {
 	}
 
 	@Override
-	public String toString() {
+	public @Nullable String toString() {
 		return get();
 	}
 

module/spring-boot-devtools/src/intTest/java/org/springframework/boot/devtools/tests/JvmLauncher.java

@@ -24,6 +24,7 @@ import java.util.Arrays;
 import java.util.List;
 import java.util.regex.Pattern;
 
+import org.jspecify.annotations.Nullable;
 import org.junit.jupiter.api.extension.BeforeTestExecutionCallback;
 import org.junit.jupiter.api.extension.Extension;
 import org.junit.jupiter.api.extension.ExtensionContext;
@@ -43,7 +44,7 @@ class JvmLauncher implements BeforeTestExecutionCallback {
 
 	private final BuildOutput buildOutput = new BuildOutput(getClass());
 
-	private File outputDirectory;
+	private @Nullable File outputDirectory;
 
 	@Override
 	public void beforeTestExecution(ExtensionContext context) throws Exception {

module/spring-boot-devtools/src/intTest/java/org/springframework/boot/devtools/tests/LaunchedApplication.java

@@ -20,6 +20,8 @@ import java.io.File;
 import java.time.Instant;
 import java.util.function.BiFunction;
 
+import org.jspecify.annotations.Nullable;
+
 /**
  * An application launched by {@link ApplicationLauncher}.
  *
@@ -35,14 +37,14 @@ class LaunchedApplication {
 
 	private final Process localProcess;
 
-	private Process remoteProcess;
+	private @Nullable Process remoteProcess;
 
 	private final Instant launchTime = Instant.now();
 
-	private final BiFunction<Integer, File, Process> remoteProcessRestarter;
+	private final @Nullable BiFunction<Integer, File, Process> remoteProcessRestarter;
 
 	LaunchedApplication(File classesDirectory, File standardOut, File standardError, Process localProcess,
-			Process remoteProcess, BiFunction<Integer, File, Process> remoteProcessRestarter) {
+			@Nullable Process remoteProcess, @Nullable BiFunction<Integer, File, Process> remoteProcessRestarter) {
 		this.classesDirectory = classesDirectory;
 		this.standardOut = standardOut;
 		this.standardError = standardError;
@@ -63,7 +65,7 @@ class LaunchedApplication {
 		stop(this.remoteProcess);
 	}
 
-	private void stop(Process process) throws InterruptedException {
+	private void stop(@Nullable Process process) throws InterruptedException {
 		if (process != null) {
 			process.destroy();
 			process.waitFor();

module/spring-boot-devtools/src/intTest/java/org/springframework/boot/devtools/tests/package-info.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2012-present 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+@NullMarked
+package org.springframework.boot.devtools.tests;
+
+import org.jspecify.annotations.NullMarked;

module/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/test/MockClientHttpRequestFactory.java

@@ -24,6 +24,8 @@ import java.util.Deque;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicLong;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
@@ -105,11 +107,11 @@ public class MockClientHttpRequestFactory implements ClientHttpRequestFactory {
 
 		private final int delay;
 
-		private final byte[] payload;
+		private final byte @Nullable [] payload;
 
 		private final HttpStatus status;
 
-		Response(int delay, byte[] payload, HttpStatus status) {
+		Response(int delay, byte @Nullable [] payload, HttpStatus status) {
 			this.delay = delay;
 			this.payload = payload;
 			this.status = status;

module/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/test/package-info.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2012-present 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+@NullMarked
+package org.springframework.boot.devtools.test;
+
+import org.jspecify.annotations.NullMarked;

module/spring-boot-devtools/src/test/java/org/springframework/boot/loader/launch/FakeJarLauncher.java

@@ -18,6 +18,8 @@ package org.springframework.boot.loader.launch;
 
 import java.util.function.Consumer;
 
+import org.jspecify.annotations.Nullable;
+
 /**
  * Fake launcher in the {@code org.springframework.boot.loader.launch} package used in
  * {@code MainMethodTests}.
@@ -26,13 +28,15 @@ import java.util.function.Consumer;
  */
 public final class FakeJarLauncher {
 
-	public static Consumer<String[]> action;
+	public static @Nullable Consumer<String[]> action;
 
 	private FakeJarLauncher() {
 	}
 
 	public static void main(String... args) {
-		action.accept(args);
+		if (action != null) {
+			action.accept(args);
+		}
 	}
 
 }

module/spring-boot-devtools/src/test/java/org/springframework/boot/loader/launch/package-info.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2012-present 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+@NullMarked
+package org.springframework.boot.loader.launch;
+
+import org.jspecify.annotations.NullMarked;