Some various simple fixes

* Fix `SimpleRetryPolicy` for NPE when `context.getLastThrowable()` is `null`
Set `NO_RECOVERY` if it cannot retry and that exception is null
* Fix `RecoverAnnotationRecoveryHandlerTests` for a proper return value
in the composite `recoverByComposedRetryableAnnotationName` annotation test

src/main/java/org/springframework/retry/policy/SimpleRetryPolicy.java

@@ -210,7 +210,7 @@ public class SimpleRetryPolicy implements RetryPolicy {
 	public boolean canRetry(RetryContext context) {
 		Throwable t = context.getLastThrowable();
 		boolean can = (t == null || retryForException(t)) && context.getRetryCount() < getMaxAttempts();
-		if (!can && !this.recoverableClassifier.classify(t)) {
+		if (!can && t != null && !this.recoverableClassifier.classify(t)) {
 			context.setAttribute(RetryContext.NO_RECOVERY, true);
 		}
 		else {

src/test/java/org/springframework/retry/annotation/RecoverAnnotationRecoveryHandlerTests.java

@@ -43,7 +43,7 @@ import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
  * @author Randell Callahan
  * @author Nathanaël Roberts
  * @author Maksim Kita
- * @Author Gianluca Medici
+ * @author Gianluca Medici
  */
 public class RecoverAnnotationRecoveryHandlerTests {
 
@@ -661,7 +661,7 @@ public class RecoverAnnotationRecoveryHandlerTests {
 		}
 
 		public int barRecover(Throwable throwable, String name) {
-			return 2;
+			return 4;
 		}
 
 	}