diff --git a/dolphinscheduler-common/src/main/java/org/apache/dolphinscheduler/common/utils/JSONUtils.java b/dolphinscheduler-common/src/main/java/org/apache/dolphinscheduler/common/utils/JSONUtils.java
index 63611cc7d6..c78ceb2d5c 100644
--- a/dolphinscheduler-common/src/main/java/org/apache/dolphinscheduler/common/utils/JSONUtils.java
+++ b/dolphinscheduler-common/src/main/java/org/apache/dolphinscheduler/common/utils/JSONUtils.java
@@ -187,7 +187,7 @@ public class JSONUtils {
      */
     public static Map<String, String> toMap(String json) {
         if (StringUtils.isEmpty(json)) {
-            return new HashMap<>();
+            return null;
         }
 
         try {
@@ -196,7 +196,7 @@ public class JSONUtils {
             logger.error("json to map exception!", e);
         }
 
-        return new HashMap<>();
+        return null;
     }
 
     /**
diff --git a/dolphinscheduler-server/src/main/java/org/apache/dolphinscheduler/server/worker/task/datax/DataxTask.java b/dolphinscheduler-server/src/main/java/org/apache/dolphinscheduler/server/worker/task/datax/DataxTask.java
index 723ded4f2f..4939456ce0 100755
--- a/dolphinscheduler-server/src/main/java/org/apache/dolphinscheduler/server/worker/task/datax/DataxTask.java
+++ b/dolphinscheduler-server/src/main/java/org/apache/dolphinscheduler/server/worker/task/datax/DataxTask.java
@@ -277,7 +277,6 @@ public class DataxTask extends AbstractTask {
                 dataSourceCfg, dataXParameters.getSql());
 
         ArrayNode columnArr = writerParam.putArray("column");
-        columnArr.addAll()
         for (String column : columns) {
             columnArr.add(column);
         }