Added more fixes for missing exceptions in JsonUtils.

Change-Id: I7c4bd43aa23b6041dbc837c9d025a3cf13b9de25
diff --git a/core/src/main/java/de/ids_mannheim/korap/utils/JsonUtils.java b/core/src/main/java/de/ids_mannheim/korap/utils/JsonUtils.java
index d011ba7..b018688 100644
--- a/core/src/main/java/de/ids_mannheim/korap/utils/JsonUtils.java
+++ b/core/src/main/java/de/ids_mannheim/korap/utils/JsonUtils.java
@@ -26,12 +26,13 @@
     private JsonUtils () {}
 
 
-    public static String toJSON (Object values) {
+    public static String toJSON (Object values) throws KustvaktException {
         try {
             return mapper.writeValueAsString(values);
         }
         catch (JsonProcessingException e) {
-            return e.getMessage();
+            throw new KustvaktException(StatusCodes.SERIALIZATION_FAILED,
+                    "Failed serializing object in json", e);
         }
     }
 
@@ -90,7 +91,7 @@
         }
         catch (IOException e) {
             throw new KustvaktException(StatusCodes.DESERIALIZATION_FAILED,
-                    "Failed deserializing json object: " + json, json, e);
+                    e.getMessage(), json, e);
         }
         return t;
     }
diff --git a/core/src/main/java/de/ids_mannheim/korap/utils/KoralCollectionQueryBuilder.java b/core/src/main/java/de/ids_mannheim/korap/utils/KoralCollectionQueryBuilder.java
index 361ab2b..71b8d57 100644
--- a/core/src/main/java/de/ids_mannheim/korap/utils/KoralCollectionQueryBuilder.java
+++ b/core/src/main/java/de/ids_mannheim/korap/utils/KoralCollectionQueryBuilder.java
@@ -2,8 +2,6 @@
 
 import java.util.List;
 
-import javax.ws.rs.WebApplicationException;
-
 import org.springframework.beans.factory.annotation.Autowired;
 
 import com.fasterxml.jackson.databind.JsonNode;