Merge branch '2.3.x'

Closes gh-22202

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

@@ -86,6 +86,11 @@ class BootJarIntegrationTests extends AbstractBootArchiveIntegrationTests {
 				.getOutcome()).isEqualTo(TaskOutcome.SUCCESS);
 	}
 
+	@TestTemplate
+	void layersWithCustomSourceSet() throws IOException {
+		assertThat(this.gradleBuild.build("bootJar").task(":bootJar").getOutcome()).isEqualTo(TaskOutcome.SUCCESS);
+	}
+
 	@TestTemplate
 	void implicitLayers() throws IOException {
 		writeMainClass();

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

@@ -0,0 +1,36 @@
+plugins {
+	id 'java'
+	id 'org.springframework.boot' version '{version}'
+}
+
+sourceSets {
+	custom
+}
+
+bootJar {
+	mainClassName = 'com.example.Application'
+	layered()
+}
+
+repositories {
+	mavenCentral()
+	maven { url "file:repository" }
+}
+
+dependencies {
+	implementation("com.example:library:1.0-SNAPSHOT")
+	implementation("org.apache.commons:commons-lang3:3.9")
+	implementation("org.springframework:spring-core:5.2.5.RELEASE")
+}
+
+task listLayers(type: JavaExec) {
+	classpath = bootJar.outputs.files
+	systemProperties = [ "jarmode": "layertools" ]
+	args "list"
+}
+
+task extractLayers(type: JavaExec) {
+	classpath = bootJar.outputs.files
+	systemProperties = [ "jarmode": "layertools" ]
+	args "extract"
+}