Polish async method execution infrastructure

In anticipation of substantive changes required to implement @Async
executor qualification, the following updates have been made to the
components and infrastructure supporting @Async functionality:

 - Fix trailing whitespace and indentation errors
 - Fix generics warnings
 - Add Javadoc where missing, update to use {@code} tags, etc.
 - Avoid NPE in AopUtils#canApply
 - Organize imports to follow conventions
 - Remove System.out.println statements from tests
 - Correct various punctuation and grammar problems

spring-aspects/src/test/java/org/springframework/scheduling/aspectj/AnnotationAsyncExecutionAspectTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2010 the original author or authors.
+ * Copyright 2002-2012 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.
@@ -20,31 +20,31 @@ import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
 
-import junit.framework.Assert;
-
-import static junit.framework.Assert.*;
-
 import org.junit.Before;
 import org.junit.Test;
 import org.springframework.core.task.SimpleAsyncTaskExecutor;
 import org.springframework.scheduling.annotation.Async;
 import org.springframework.scheduling.annotation.AsyncResult;
 
+import static org.junit.Assert.*;
+
 /**
+ * Unit tests for {@link AnnotationAsyncExecutionAspect}.
+ *
  * @author Ramnivas Laddad
  */
 public class AnnotationAsyncExecutionAspectTests {
 
-	private static final long WAIT_TIME = 1000; //milli seconds
+	private static final long WAIT_TIME = 1000; //milliseconds
 
 	private CountingExecutor executor;
-	
+
 	@Before
 	public void setUp() {
 		executor = new CountingExecutor();
 		AnnotationAsyncExecutionAspect.aspectOf().setExecutor(executor);
 	}
-	
+
 	@Test
 	public void asyncMethodGetsRoutedAsynchronously() {
 		ClassWithoutAsyncAnnotation obj = new ClassWithoutAsyncAnnotation();
@@ -54,7 +54,7 @@ public class AnnotationAsyncExecutionAspectTests {
 		assertEquals(1, executor.submitStartCounter);
 		assertEquals(1, executor.submitCompleteCounter);
 	}
-	
+
 	@Test
 	public void asyncMethodReturningFutureGetsRoutedAsynchronouslyAndReturnsAFuture() throws InterruptedException, ExecutionException {
 		ClassWithoutAsyncAnnotation obj = new ClassWithoutAsyncAnnotation();
@@ -73,8 +73,8 @@ public class AnnotationAsyncExecutionAspectTests {
 		assertEquals(1, obj.counter);
 		assertEquals(0, executor.submitStartCounter);
 		assertEquals(0, executor.submitCompleteCounter);
-	}	
-	
+	}
+
 	@Test
 	public void voidMethodInAsyncClassGetsRoutedAsynchronously() {
 		ClassWithAsyncAnnotation obj = new ClassWithAsyncAnnotation();
@@ -102,13 +102,14 @@ public class AnnotationAsyncExecutionAspectTests {
 		assertEquals(5, returnValue);
 		assertEquals(0, executor.submitStartCounter);
 		assertEquals(0, executor.submitCompleteCounter);
-	}	
+	}
+
 
 	@SuppressWarnings("serial")
 	private static class CountingExecutor extends SimpleAsyncTaskExecutor {
 		int submitStartCounter;
 		int submitCompleteCounter;
-		
+
 		@Override
 		public <T> Future<T> submit(Callable<T> task) {
 			submitStartCounter++;
@@ -119,52 +120,56 @@ public class AnnotationAsyncExecutionAspectTests {
 			}
 			return future;
 		}
-		
+
 		public synchronized void waitForCompletion() {
 			try {
 				wait(WAIT_TIME);
 			} catch (InterruptedException e) {
-				Assert.fail("Didn't finish the async job in " + WAIT_TIME + " milliseconds");
+				fail("Didn't finish the async job in " + WAIT_TIME + " milliseconds");
 			}
 		}
 	}
-	
+
+
 	static class ClassWithoutAsyncAnnotation {
 		int counter;
-		
+
 		@Async public void incrementAsync() {
 			counter++;
 		}
-		
+
 		public void increment() {
 			counter++;
 		}
-		
+
 		@Async public Future<Integer> incrementReturningAFuture() {
 			counter++;
 			return new AsyncResult<Integer>(5);
 		}
-		
-		// It should be an error to attach @Async to a method that returns a non-void
-		// or non-Future.
-		// We need to keep this commented out, otherwise there will be a compile-time error. 
-		// Please uncomment and re-comment this periodically to check that the compiler 
-		// produces an error message due to the 'declare error' statement 
-		// in AnnotationAsyncExecutionAspect
+
+		/**
+		 * It should raise an error to attach @Async to a method that returns a non-void
+		 * or non-Future. This method must remain commented-out, otherwise there will be a
+		 * compile-time error. Uncomment to manually verify that the compiler produces an
+		 * error message due to the 'declare error' statement in
+		 * {@link AnnotationAsyncExecutionAspect}.
+		 */
 //		@Async public int getInt() {
 //			return 0;
 //		}
 	}
-	
+
+
 	@Async
 	static class ClassWithAsyncAnnotation {
 		int counter;
-		
+
 		public void increment() {
 			counter++;
 		}
-		
-		// Manually check that there is a warning from the 'declare warning' statement in AnnotationAsynchExecutionAspect
+
+		// Manually check that there is a warning from the 'declare warning' statement in
+		// AnnotationAsyncExecutionAspect
 		public int return5() {
 			return 5;
 		}