DATAMONGO-1423 - Polishing.

Orignal pull request: #365.

Author: odrotbohm

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/MappingMongoConverter.java

@@ -993,21 +993,30 @@ public Object convertToMongoType(Object obj, TypeInformation<?> typeInformation)
 		}
 
 		if (obj instanceof DBObject) {
+
 			DBObject newValueDbo = new BasicDBObject();
+
 			for (String vk : ((DBObject) obj).keySet()) {
+
 				Object o = ((DBObject) obj).get(vk);
 				newValueDbo.put(vk, convertToMongoType(o, typeHint));
 			}
+
 			return newValueDbo;
 		}
 
 		if (obj instanceof Map) {
+
 			Map<Object, Object> converted = new LinkedHashMap<Object, Object>();
 
-			for (Map.Entry<Object, Object> entry : ((Map<Object, Object>) obj).entrySet()) {
-				converted.put(convertToMongoType(entry.getKey()), convertToMongoType(entry.getValue(),
-						typeHint != null && typeHint.getMapValueType() != null ? typeHint.getMapValueType() : typeHint));
+			for (Entry<Object, Object> entry : ((Map<Object, Object>) obj).entrySet()) {
+
+				TypeInformation<? extends Object> valueTypeHint = typeHint != null && typeHint.getMapValueType() != null
+						? typeHint.getMapValueType() : typeHint;
+
+				converted.put(convertToMongoType(entry.getKey()), convertToMongoType(entry.getValue(), valueTypeHint));
 			}
+
 			return new BasicDBObject(converted);
 		}
 

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/convert/UpdateMapperUnitTests.java

@@ -916,6 +916,7 @@ public void mapsMaxCorrectly() {
 	 * @see DATAMONGO-1423
 	 */
 	@Test
+	@SuppressWarnings("unchecked")
 	public void mappingShouldConsiderCustomConvertersForEnumMapKeys() {
 
 		CustomConversions conversions = new CustomConversions(