Prevent AspectJ from loading aspects too early

Previously, AspectJ would find META-INF/aop.xml almost as soon as
the jar was launched, and before LaunchedURLClassLoader had been
created. This meant that AspectJ would attempt to load aspects listed
in META-INF/aop.xml but that were package in BOOT-INF/classes and,
therefore, could not be loaded.

This commit updates the Repackager so that a META-INF/aop.xml file
is moved into BOOT-INF/classes. This ensures that it isn't visible
to the app class loader so it won't be loaded to early. It will
now be loaded by LaunchedURLClassLoader which can also load the
compiled aspects that aop.xml references.

Closes gh-7587

spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/Repackager.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2017 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.
@@ -432,7 +432,8 @@ public class Repackager {
 			if (entry.getName().equals("META-INF/INDEX.LIST")) {
 				return null;
 			}
-			if (entry.getName().startsWith("META-INF/")
+			if ((entry.getName().startsWith("META-INF/")
+					&& !entry.getName().equals("META-INF/aop.xml"))
 					|| entry.getName().startsWith("BOOT-INF/")) {
 				return entry;
 			}

spring-boot-tools/spring-boot-loader-tools/src/test/java/org/springframework/boot/loader/tools/RepackagerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2017 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.
@@ -593,6 +593,26 @@ public class RepackagerTests {
 		jarFile.close();
 	}
 
+	@Test
+	public void metaInfAopXmlIsMovedBeneathBootInfClassesWhenRepackaged()
+			throws Exception {
+		this.testJarFile.addClass("A.class", ClassWithMainMethod.class);
+		this.testJarFile.addFile("META-INF/aop.xml",
+				this.temporaryFolder.newFile("aop.xml"));
+		File source = this.testJarFile.getFile();
+		File dest = this.temporaryFolder.newFile("dest.jar");
+		Repackager repackager = new Repackager(source);
+		repackager.repackage(dest, NO_LIBRARIES);
+		JarFile jarFile = new JarFile(dest);
+		try {
+			assertThat(jarFile.getEntry("META-INF/aop.xml")).isNull();
+			assertThat(jarFile.getEntry("BOOT-INF/classes/META-INF/aop.xml")).isNotNull();
+		}
+		finally {
+			jarFile.close();
+		}
+	}
+
 	private boolean hasLauncherClasses(File file) throws IOException {
 		return hasEntry(file, "org/springframework/boot/")
 				&& hasEntry(file, "org/springframework/boot/loader/JarLauncher.class");