Do not use lambda for task action as it breaks up-to-date checks

Due to gradle/gradle#5510, using a lambda for a task action breaks
up-to-date checks in certain circumstances.

This commit updates JavaPluginAction to use an inner-class in place
of a lambda for the action that it adds to JavaCompile tasks. A test
has not been added as it does not appear to be possible to reproduce
it with a TestKit-based test.

Closes gh-14054

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/plugin/JavaPluginAction.java

@@ -26,6 +26,7 @@ import java.util.concurrent.Callable;
 import org.gradle.api.Action;
 import org.gradle.api.Plugin;
 import org.gradle.api.Project;
+import org.gradle.api.Task;
 import org.gradle.api.file.FileCollection;
 import org.gradle.api.internal.artifacts.publish.ArchivePublishArtifact;
 import org.gradle.api.plugins.ApplicationPlugin;
@@ -145,20 +146,22 @@ final class JavaPluginAction implements PluginApplicationAction {
 	}
 
 	private void configureAdditionalMetadataLocations(JavaCompile compile) {
-		compile.doFirst((task) -> {
+		compile.doFirst(new AdditionalMetadataLocationsConfigurer());
+	}
+
+	private static class AdditionalMetadataLocationsConfigurer implements Action<Task> {
+
+		@Override
+		public void execute(Task task) {
+			if (!(task instanceof JavaCompile)) {
+				return;
+			}
+			JavaCompile compile = (JavaCompile) task;
 			if (hasConfigurationProcessorOnClasspath(compile)) {
 				findMatchingSourceSet(compile).ifPresent(
 						(sourceSet) -> configureAdditionalMetadataLocations(compile,
 								sourceSet));
 			}
-		});
-	}
-
-	private Optional<SourceSet> findMatchingSourceSet(JavaCompile compile) {
-		return compile.getProject().getConvention().getPlugin(JavaPluginConvention.class)
-				.getSourceSets().stream().filter((sourceSet) -> sourceSet
-						.getCompileJavaTaskName().equals(compile.getName()))
-				.findFirst();
 		}
 
 		private boolean hasConfigurationProcessorOnClasspath(JavaCompile compile) {
@@ -169,13 +172,23 @@ final class JavaPluginAction implements PluginApplicationAction {
 					(name) -> name.startsWith("spring-boot-configuration-processor"));
 		}
 
+		private Optional<SourceSet> findMatchingSourceSet(JavaCompile compile) {
+			return compile
+					.getProject().getConvention().getPlugin(JavaPluginConvention.class)
+					.getSourceSets().stream().filter((sourceSet) -> sourceSet
+							.getCompileJavaTaskName().equals(compile.getName()))
+					.findFirst();
+		}
+
 		private void configureAdditionalMetadataLocations(JavaCompile compile,
 				SourceSet sourceSet) {
-		String locations = StringUtils
+			String locations = StringUtils.collectionToCommaDelimitedString(
-				.collectionToCommaDelimitedString(sourceSet.getResources().getSrcDirs());
+					sourceSet.getResources().getSrcDirs());
 			compile.getOptions().getCompilerArgs().add(
 					"-Aorg.springframework.boot.configurationprocessor.additionalMetadataLocations="
 							+ locations);
 		}
 
+	}
+
 }