WINK-373 - Fix NPE when EntityType is null

Patch provided by TERAJIMA Motoyuki

git-svn-id: https://svn.apache.org/repos/asf/incubator/wink/trunk@1415943 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/wink-client/src/main/java/org/apache/wink/client/internal/ResourceImpl.java b/wink-client/src/main/java/org/apache/wink/client/internal/ResourceImpl.java
index 49c272e..2c63607 100644
--- a/wink-client/src/main/java/org/apache/wink/client/internal/ResourceImpl.java
+++ b/wink-client/src/main/java/org/apache/wink/client/internal/ResourceImpl.java
@@ -198,11 +198,12 @@
 
     @SuppressWarnings("unchecked")
     public <T> T invoke(String method, EntityType<T> responseEntity, Object requestEntity) {
-        ClientResponse response =
-            invoke(method, responseEntity.getRawClass(), responseEntity.getType(), requestEntity);
         if (responseEntity == null) {
+            invoke(method, null, null, requestEntity);
             return null;
         }
+        ClientResponse response =
+            invoke(method, responseEntity.getRawClass(), responseEntity.getType(), requestEntity);
         if (ClientResponse.class.equals(responseEntity.getRawClass())) {
             return (T)response;
         }