Fix reusable archive creation with Gradle 4.1 and later

Closes gh-11468

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/tasks/bundling/AbstractBootArchiveIntegrationTests.java

@@ -29,6 +29,7 @@ import org.junit.runner.RunWith;
 
 import org.springframework.boot.gradle.junit.GradleCompatibilitySuite;
 import org.springframework.boot.gradle.testkit.GradleBuild;
+import org.springframework.boot.loader.tools.FileUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -56,6 +57,21 @@ public abstract class AbstractBootArchiveIntegrationTests {
 				.getOutcome()).isEqualTo(TaskOutcome.SUCCESS);
 	}
 
+	@Test
+	public void reproducibleArchive() throws InvalidRunnerConfigurationException,
+			UnexpectedBuildFailure, IOException, InterruptedException {
+		assertThat(this.gradleBuild.build(this.taskName).task(":" + this.taskName)
+				.getOutcome()).isEqualTo(TaskOutcome.SUCCESS);
+		File jar = new File(this.gradleBuild.getProjectDir(), "build/libs")
+				.listFiles()[0];
+		String firstHash = FileUtils.sha1Hash(jar);
+		Thread.sleep(1500);
+		assertThat(this.gradleBuild.build("clean", this.taskName)
+				.task(":" + this.taskName).getOutcome()).isEqualTo(TaskOutcome.SUCCESS);
+		String secondHash = FileUtils.sha1Hash(jar);
+		assertThat(firstHash).isEqualTo(secondHash);
+	}
+
 	@Test
 	public void upToDateWhenBuiltTwice() throws InvalidRunnerConfigurationException,
 			UnexpectedBuildFailure, IOException {

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootJarIntegrationTests-reproducibleArchive.gradle

@@ -0,0 +1,14 @@
+buildscript {
+	dependencies {
+		classpath files(pluginClasspath.split(','))
+	}
+}
+
+apply plugin: 'java'
+apply plugin: 'org.springframework.boot'
+
+bootJar {
+	mainClassName = 'com.example.Application'
+	preserveFileTimestamps = false
+    reproducibleFileOrder = true
+}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootWarIntegrationTests-reproducibleArchive.gradle

@@ -0,0 +1,14 @@
+buildscript {
+	dependencies {
+		classpath files(pluginClasspath.split(','))
+	}
+}
+
+apply plugin: 'war'
+apply plugin: 'org.springframework.boot'
+
+bootWar {
+	mainClassName = 'com.example.Application'
+	preserveFileTimestamps = false
+    reproducibleFileOrder = true
+}