convert list field failure

src/main/java/net/badata/protobuf/converter/Converter.java

@@ -60,7 +60,6 @@ public static Converter create() {
 	 *
 	 * @param fieldsIgnore Map of fields that has to be ignored by this converter instance.
 	 * @return Converter instance.
-	 *
 	 * @deprecated use {@code create(Configuration)} instead.
 	 */
 	@Deprecated
@@ -180,7 +179,7 @@ private List<Field> getDomainFields(final Class clazz) {
 
 		fields.addAll(Arrays.asList(clazz.getDeclaredFields()));
 
-		if(configuration.withInheritedFields()) {
+		if (configuration.withInheritedFields()) {
 			Class superClazz = clazz.getSuperclass();
 			if (superClazz != null) {
 				fields.addAll(getDomainFields(superClazz));
@@ -239,8 +238,10 @@ private <T, E extends Message, K extends Collection> K toProtobuf(final Class<K>
 			final Class<E> protobufClass, final Collection<T> domainCollection) {
 		Collection<E> protobufCollection = List.class.isAssignableFrom(collectionClass) ? new ArrayList<E>() : new
 				HashSet<E>();
-		for (T domain : domainCollection) {
-			protobufCollection.add(toProtobuf(protobufClass, domain));
+		if (domainCollection != null) {
+			for (T domain : domainCollection) {
+				protobufCollection.add(toProtobuf(protobufClass, domain));
+			}
 		}
 		return (K) protobufCollection;
 	}
@@ -314,17 +315,19 @@ private void fillProtobufField(final FieldResolver fieldResolver, final MappingR
 				if (FieldUtils.isComplexType(collectionType)) {
 					Class<? extends Message> protobufCollectionClass = MessageUtils.getMessageCollectionType(
 							mappingResult.getDestination(), FieldUtils.createProtobufGetterName(fieldResolver));
-					mappedValue = createProtobufValueList(protobufCollectionClass, (Collection) mappedValue);
+					mappedValue = createProtobufValueList(protobufCollectionClass, field.getType(),
+							(Collection) mappedValue);
 				}
 			case MAPPED:
 			default:
 				fieldWriter.write(fieldResolver, mappedValue);
 		}
 	}
 
-	private <E extends Message> Collection<?> createProtobufValueList(final Class<E> type, final Collection<?>
-			domainCollection) {
-		return createNestedConverter().toProtobuf(domainCollection.getClass(), type, domainCollection);
+	private <E extends Message> Collection<?> createProtobufValueList(final Class<E> type, final Class<?>
+			domainCollectionClass, final Collection<?> domainCollection) {
+		return createNestedConverter()
+				.toProtobuf((Class<? extends Collection>) domainCollectionClass, type, domainCollection);
 	}
 
 }

src/test/java/net/badata/protobuf/converter/ConverterTest.java

@@ -84,13 +84,13 @@ private void createTestDomain() {
 		testDomain.setFieldConversionValue(fieldConverterTest);
 		testDomain.setSimpleListValue(Arrays.asList("110"));
 
-
 		ConverterDomain.PrimitiveTest primitiveTestItem = new ConverterDomain.PrimitiveTest();
 		primitiveTestItem.setIntValue(-1001);
 		testDomain.setComplexListValue(Arrays.asList(primitiveTestItem));
 		ConverterDomain.PrimitiveTest primitiveTestSItem = new ConverterDomain.PrimitiveTest();
 		primitiveTestItem.setIntValue(-1002);
 		testDomain.setComplexSetValue(new HashSet<ConverterDomain.PrimitiveTest>(Arrays.asList(primitiveTestSItem)));
+		testDomain.setComplexNullableCollectionValue(null);
 	}
 
 	private void createIgnoredFieldsMap() {
@@ -144,6 +144,8 @@ public void testProtobufToDomain() {
 				result.getComplexListValue().get(0).getIntValue());
 		Assert.assertEquals(testProtobuf.getComplexSetValue(0).getIntValue(),
 				result.getComplexSetValue().iterator().next().getIntValue());
+
+		Assert.assertTrue(result.getComplexNullableCollectionValue().isEmpty());
 	}
 
 	@Test
@@ -198,6 +200,8 @@ public void testDomainToProtobuf() {
 				result.getComplexListValue(0).getIntValue());
 		Assert.assertEquals(testDomain.getComplexSetValue().iterator().next().getIntValue(),
 				result.getComplexSetValue(0).getIntValue());
+
+		Assert.assertTrue(result.getComplexNullableCollectionValueList().isEmpty());
 	}
 
 	@Test

src/test/java/net/badata/protobuf/converter/MultiMappingTest.java

@@ -101,4 +101,6 @@ public void testMultiMapping() {
 		Assert.assertEquals((Object) testProtobuf.getMultiMappingListValue(0).getLongValueChanged(),
 				listChild.getLongValue());
 	}
+
+
 }

src/test/java/net/badata/protobuf/converter/domain/ConverterDomain.java

@@ -53,6 +53,8 @@ public static class Test {
 		private List<PrimitiveTest> complexListValue;
 		@ProtoField(converter = SetListConverterImpl.class)
 		private Set<PrimitiveTest> complexSetValue;
+		@ProtoField
+		private List<PrimitiveTest> complexNullableCollectionValue;
 
 
 		public Long getLongValue() {
@@ -151,6 +153,14 @@ public Set<PrimitiveTest> getComplexSetValue() {
 		public void setComplexSetValue(final Set<PrimitiveTest> complexSetValue) {
 			this.complexSetValue = complexSetValue;
 		}
+
+		public List<PrimitiveTest> getComplexNullableCollectionValue() {
+			return complexNullableCollectionValue;
+		}
+
+		public void setComplexNullableCollectionValue(final List<PrimitiveTest> complexNullableCollectionValue) {
+			this.complexNullableCollectionValue = complexNullableCollectionValue;
+		}
 	}
 
 	@ProtoClass(ConverterProto.PrimitiveTest.class)