Merge pull request #215 from messagebird/Issue-213_verifyAPI

resolves issue #213

Author: denizkilic

api/src/main/java/com/messagebird/MessageBirdServiceImpl.java

@@ -2,10 +2,7 @@
 
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
 import com.fasterxml.jackson.core.JsonProcessingException;
-import com.fasterxml.jackson.databind.DeserializationFeature;
-import com.fasterxml.jackson.databind.JsonNode;
-import com.fasterxml.jackson.databind.MapperFeature;
-import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.*;
 import com.messagebird.exceptions.GeneralException;
 import com.messagebird.exceptions.NotFoundException;
 import com.messagebird.exceptions.UnauthorizedException;
@@ -593,6 +590,7 @@ public <P> HttpURLConnection getConnection(final String serviceUrl, final P body
             connection.setRequestProperty("Content-Type", "application/json");
             ObjectMapper mapper = new ObjectMapper();
             mapper.setSerializationInclusion(Include.NON_NULL);
+            mapper.enable(SerializationFeature.WRITE_ENUMS_USING_TO_STRING);
             // Specifically set the date format for POST requests so scheduled
             // messages and other things relying on specific date formats don't
             // fail when sending.

api/src/main/java/com/messagebird/objects/Language.java

@@ -11,7 +11,7 @@ public enum Language {
     EN_US("en-us"),
     ES_ES("es-es"),
     FR_FR("fr-fr"),
-    RU_RU("ru_ru"),
+    RU_RU("ru-ru"),
     ZH_CN("zh-cn"),
     EN_AU("en-au"),
     ES_MX("es-mx"),