No need to call getError on writeResult. any errors for writeConcern level...

No need to call getError on writeResult. any errors for writeConcern level will throw exceptions and be caught in catch block

mongodb/src/main/java/com/yahoo/ycsb/db/MongoDbClient.java

@@ -194,7 +194,7 @@ public class MongoDbClient extends DB {
             DBCollection collection = db.getCollection(table);
             DBObject q = new BasicDBObject().append("_id", key);
             WriteResult res = collection.remove(q, writeConcern);
-            return res.getN() == 1 ? 0 : 1;
+            return 0;
         }
         catch (Exception e) {
             System.err.println(e.toString());
@@ -236,7 +236,7 @@ public class MongoDbClient extends DB {
                 r.put(entry.getKey(), entry.getValue().toArray());
             }
             WriteResult res = collection.insert(r, writeConcern);
-            return res.getError() == null ? 0 : 1;
+            return 0;
         }
         catch (Exception e) {
             e.printStackTrace();
@@ -341,7 +341,7 @@ public class MongoDbClient extends DB {
             u.put("$set", fieldsToSet);
             WriteResult res = collection.update(q, u, false, false,
                     writeConcern);
-            return res.getN() == 1 ? 0 : 1;
+            return 0;
         }
         catch (Exception e) {
             System.err.println(e.toString());