GH-1077 Update AWSLambdaUtils.java with null check

Resolves #1077 by checking for a null package, which can happen when the inputType is a Message that encloses a primitive generic type

Update AWSTypesMessageConverter.java

Added additional fixes for #1077 in AWTypesMessageConverter

Update FunctionInvokerTests.java

Added unit tests to verify fix for #1077

Checkstyle fix

Resolves #1078

spring-cloud-function-adapters/spring-cloud-function-adapter-aws/src/main/java/org/springframework/cloud/function/adapter/aws/AWSLambdaUtils.java

@@ -74,7 +74,9 @@ public final class AWSLambdaUtils {
 		if (FunctionTypeUtils.isMessage(inputType) || FunctionTypeUtils.isPublisher(inputType)) {
 			inputType = FunctionTypeUtils.getImmediateGenericType(inputType, 0);
 		}
-		return FunctionTypeUtils.getRawType(inputType).getPackage().getName().startsWith("com.amazonaws.services.lambda.runtime.events");
+		return FunctionTypeUtils.getRawType(inputType).getPackage() != null &&
+				FunctionTypeUtils.getRawType(inputType).getPackage().getName().startsWith(
+						"com.amazonaws.services.lambda.runtime.events");
 	}
 
 	@SuppressWarnings("rawtypes")

spring-cloud-function-adapters/spring-cloud-function-adapter-aws/src/main/java/org/springframework/cloud/function/adapter/aws/AWSTypesMessageConverter.java

@@ -63,7 +63,8 @@ class AWSTypesMessageConverter extends JsonMessageConverter {
 			return ((boolean) message.getHeaders().get(AWSLambdaUtils.AWS_EVENT));
 		}
 		//TODO Do we really need the ^^ above? It seems like the line below dows the trick
-		else if (targetClass.getPackage().getName().startsWith("com.amazonaws.services.lambda.runtime.events")) {
+		else if (targetClass.getPackage() != null &&
+				targetClass.getPackage().getName().startsWith("com.amazonaws.services.lambda.runtime.events")) {
 			return true;
 		}
 		return false;
@@ -75,7 +76,8 @@ class AWSTypesMessageConverter extends JsonMessageConverter {
 			return message.getPayload();
 		}
 
-		if (targetClass.getPackage().getName().startsWith("com.amazonaws.services.lambda.runtime.events")) {
+		if (targetClass.getPackage() != null &&
+				targetClass.getPackage().getName().startsWith("com.amazonaws.services.lambda.runtime.events")) {
 			PojoSerializer<?> serializer = LambdaEventSerializers.serializerFor(targetClass, Thread.currentThread().getContextClassLoader());
 			Object event = serializer.fromJson(new ByteArrayInputStream((byte[]) message.getPayload()));
 			return event;

spring-cloud-function-adapters/spring-cloud-function-adapter-aws/src/test/java/org/springframework/cloud/function/adapter/aws/FunctionInvokerTests.java

@@ -1407,6 +1407,21 @@ public class FunctionInvokerTests {
 		assertThat(result.get("body")).isEqualTo("\"olleh\"");
 	}
 
+	@Test
+	public void testPrimitiveMessage() throws Exception {
+		System.setProperty("MAIN_CLASS", PrimitiveConfiguration.class.getName());
+		System.setProperty("spring.cloud.function.definition", "returnByteArrayAsMessage");
+		FunctionInvoker invoker = new FunctionInvoker();
+
+		String testString = "{ \"message\": \"Hello, world!\" }";
+		InputStream targetStream = new ByteArrayInputStream(testString.getBytes());
+		ByteArrayOutputStream output = new ByteArrayOutputStream();
+		invoker.handleRequest(targetStream, output, null);
+
+		String result = output.toString();
+		assertThat(result).isEqualTo(testString);
+	}
+
 	@EnableAutoConfiguration
 	@Configuration
 	public static class AuthorizerConfiguration {
@@ -1811,6 +1826,17 @@ public class FunctionInvokerTests {
 		}
 	}
 
+	@EnableAutoConfiguration
+	@Configuration
+	public static class PrimitiveConfiguration {
+		@Bean
+		public Function<Message<byte[]>, byte[]> returnByteArrayAsMessage() {
+			return v -> {
+				return v.getPayload();
+			};
+		}
+	}
+
 	public static class Person {
 		private String name;