diff --git a/debezium-connector-mongodb/src/main/java/io/debezium/connector/mongodb/transforms/MongoDataConverter.java b/debezium-connector-mongodb/src/main/java/io/debezium/connector/mongodb/transforms/MongoDataConverter.java
index 10baba947..03962a4d6 100644
--- a/debezium-connector-mongodb/src/main/java/io/debezium/connector/mongodb/transforms/MongoDataConverter.java
+++ b/debezium-connector-mongodb/src/main/java/io/debezium/connector/mongodb/transforms/MongoDataConverter.java
@@ -8,23 +8,23 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map.Entry;
+
+import org.apache.kafka.connect.data.Schema;
 import org.apache.kafka.connect.data.SchemaBuilder;
 import org.apache.kafka.connect.data.Struct;
 import org.bson.BsonDocument;
 import org.bson.BsonType;
 import org.bson.BsonValue;
-
-import org.slf4j.LoggerFactory;
 import org.slf4j.Logger;
-import org.apache.kafka.connect.data.Schema;
+import org.slf4j.LoggerFactory;
 
 /**
  * MongoDataConverter handles translating MongoDB strings to Kafka Connect schemas and row data to Kafka
  * Connect records.
+ *
  * @author Sairam Polavarapu
  */
 public class MongoDataConverter {
-    static SchemaBuilder builder = SchemaBuilder.struct();
 
     private static final Logger LOG = LoggerFactory.getLogger(MongoDataConverter.class);
 
@@ -189,7 +189,6 @@ public static void convertFieldValue(Entry<String, BsonValue> keyvalueforStruct,
     }
 
     public static void addFieldSchema(Entry<String, BsonValue> keyValuesforSchema, SchemaBuilder builder) {
-
         String key = keyValuesforSchema.getKey();
         BsonType type = keyValuesforSchema.getValue().getBsonType();
 
diff --git a/debezium-connector-mongodb/src/main/java/io/debezium/connector/mongodb/transforms/StringToJSON.java b/debezium-connector-mongodb/src/main/java/io/debezium/connector/mongodb/transforms/StringToJSON.java
index 4ebb97d8a..4faceab24 100644
--- a/debezium-connector-mongodb/src/main/java/io/debezium/connector/mongodb/transforms/StringToJSON.java
+++ b/debezium-connector-mongodb/src/main/java/io/debezium/connector/mongodb/transforms/StringToJSON.java
@@ -5,6 +5,12 @@
  */
 package io.debezium.connector.mongodb.transforms;
 
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+
 import org.apache.kafka.common.config.ConfigDef;
 import org.apache.kafka.connect.connector.ConnectRecord;
 import org.apache.kafka.connect.data.Schema;
@@ -20,24 +26,19 @@
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.node.ObjectNode;
 
-import java.io.IOException;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Set;
-import java.util.Map.Entry;
-
 /**
  * Debezium Mongo Connector generates the CDC records in String format. Sink connectors usually are not able to parse
- * the string and insert the document as it is represented in the Source. so a user use this SMT to parse the String 
- * and insert the MongoDB document in the JSON format..
+ * the string and insert the document as it is represented in the Source. so a user use this SMT to parse the String
+ * and insert the MongoDB document in the JSON format.
+ *
  * @param <R> the subtype of {@link ConnectRecord} on which this transformation will operate
- * @author Sairam Polavarapu.
+ * @author Sairam Polavarapu
  */
 public class StringToJSON<R extends ConnectRecord<R>> implements Transformation<R> {
 
-    final ExtractField<R> afterExtractor = new ExtractField.Value<R>();
-    final ExtractField<R> patchExtractor = new ExtractField.Value<R>();
-    final ExtractField<R> keyExtractor = new ExtractField.Key<R>();
+    private final ExtractField<R> afterExtractor = new ExtractField.Value<R>();
+    private final ExtractField<R> patchExtractor = new ExtractField.Value<R>();
+    private final ExtractField<R> keyExtractor = new ExtractField.Key<R>();
 
     @Override
     public R apply(R r) {
@@ -50,21 +51,22 @@ public R apply(R r) {
         final R afterRecord = afterExtractor.apply(r);
 
         if (afterRecord.value() == null) {
-        final R patchRecord = patchExtractor.apply(r);
-        final R key = keyExtractor.apply(r);
-        ObjectNode patchEventWKey = mapper.createObjectNode();
-        JsonNode patchEvent = null;
-         try {
-              patchEvent = mapper.readTree(patchRecord.value().toString());
-             } catch (JsonProcessingException e) {
-                 e.printStackTrace();
-             } catch (IOException e) {
-                 e.printStackTrace();
-             }
+            final R patchRecord = patchExtractor.apply(r);
+            final R key = keyExtractor.apply(r);
+            ObjectNode patchEventWKey = mapper.createObjectNode();
+            JsonNode patchEvent = null;
+
+            try {
+                patchEvent = mapper.readTree(patchRecord.value().toString());
+            } catch (JsonProcessingException e) {
+                e.printStackTrace();
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
             patchEventWKey.set("$set",patchEvent.path("$set"));
             boolean hasId = patchEvent.has("_id");
             if(hasId) {
-            patchEventWKey.set("_id", patchEvent.path("_id"));
+                patchEventWKey.set("_id", patchEvent.path("_id"));
             } else {
                 patchEventWKey.set("_id", mapper.convertValue(key.key(), JsonNode.class));
             }
@@ -72,7 +74,7 @@ public R apply(R r) {
             value = BsonDocument.parse(patchEventWKey.toString());
             BsonDocument doc = new BsonDocument().append("id", value.get("_id"));
             Key = BsonDocument.parse(doc.toString());
-            
+
         } else {
             value = BsonDocument.parse(afterRecord.value().toString());
             BsonDocument doc = new BsonDocument().append("id", value.get("_id"));
@@ -88,10 +90,10 @@ public R apply(R r) {
                 Set<Entry<String, BsonValue>> keyValuesforSetSchema = val1.entrySet();
                 for (Entry<String, BsonValue> keyValuesforSetSchemaEntry : keyValuesforSetSchema) {
                     MongoDataConverter.addFieldSchema(keyValuesforSetSchemaEntry, schemabuilder);
-                    }
-                } else {
-                    MongoDataConverter.addFieldSchema(valuePairsforSchema, schemabuilder);
-                    }
+                }
+            } else {
+                MongoDataConverter.addFieldSchema(valuePairsforSchema, schemabuilder);
+            }
         }
 
         for (Entry<String, BsonValue> keyPairsforSchema : keyPairs) {
@@ -109,12 +111,12 @@ public R apply(R r) {
                 Set<Entry<String, BsonValue>> keyvalueforSetStruct = val1.entrySet();
                 for (Entry<String, BsonValue> keyvalueforSetStructEntry : keyvalueforSetStruct) {
                     MongoDataConverter.convertRecord(keyvalueforSetStructEntry, finalValueSchema, finalValueStruct);
-                    }
-                } else {
-            MongoDataConverter.convertRecord(valuePairsforStruct, finalValueSchema, finalValueStruct);
+                }
+            } else {
+                MongoDataConverter.convertRecord(valuePairsforStruct, finalValueSchema, finalValueStruct);
             }
         }
-        
+
         for (Entry<String, BsonValue> keyPairsforStruct : keyPairs) {
             MongoDataConverter.convertRecord(keyPairsforStruct, finalKeySchema, finalKeyStruct);
         }
@@ -128,6 +130,7 @@ public ConfigDef config() {
         return new ConfigDef();
     }
 
+    @Override
     public void close() {
     }