diff --git a/src/main/java/com/actiontech/dble/plan/common/field/Field.java b/src/main/java/com/actiontech/dble/plan/common/field/Field.java
index 042691169..ef02c5cb2 100644
--- a/src/main/java/com/actiontech/dble/plan/common/field/Field.java
+++ b/src/main/java/com/actiontech/dble/plan/common/field/Field.java
@@ -58,7 +58,7 @@ public abstract class Field {
             case MYSQL_TYPE_DOUBLE:
                 return new FieldDouble(name, dbName, table, orgTable, charsetIndex, fieldLength, decimals, flags);
             case MYSQL_TYPE_NULL:
-                return FieldNull.getInstance();
+                return new FieldNull(name, "", table, "", 63, 0, 0, 0);
             case MYSQL_TYPE_TIMESTAMP:
                 return new FieldTimestamp(name, dbName, table, orgTable, charsetIndex, fieldLength, decimals, flags);
             case MYSQL_TYPE_LONGLONG:
@@ -82,7 +82,7 @@ public abstract class Field {
                 return new FieldVarstring(name, dbName, table, orgTable, charsetIndex, fieldLength, decimals, flags);
             case MYSQL_TYPE_STRING:
                 return new FieldString(name, dbName, table, orgTable, charsetIndex, fieldLength, decimals, flags);
-            /** --not support below, because select * change to string, can't get the origin type-- **/
+            /* --not support below, because select * change to string, can't get the origin type-- **/
             case MYSQL_TYPE_ENUM:
                 return new FieldEnum(name, dbName, table, orgTable, charsetIndex, fieldLength, decimals, flags);
             case MYSQL_TYPE_SET:
@@ -280,14 +280,6 @@ public abstract class Field {
         this.charsetIndex = charsetIndex;
     }
 
-    public String getJavaCharsetName() {
-        return javaCharsetName;
-    }
-
-    public void setJavaCharsetName(String javaCharsetName) {
-        this.javaCharsetName = javaCharsetName;
-    }
-
     public long getFlags() {
         return flags;
     }
diff --git a/src/main/java/com/actiontech/dble/plan/common/field/FieldNull.java b/src/main/java/com/actiontech/dble/plan/common/field/FieldNull.java
index 977765f84..b3649b145 100644
--- a/src/main/java/com/actiontech/dble/plan/common/field/FieldNull.java
+++ b/src/main/java/com/actiontech/dble/plan/common/field/FieldNull.java
@@ -12,11 +12,6 @@ import java.math.BigDecimal;
 import java.math.BigInteger;
 
 public class FieldNull extends FieldStr {
-    private static FieldNull instance = new FieldNull("NULL", "", "", "", 63, 0, 0, 0);
-
-    public static FieldNull getInstance() {
-        return instance;
-    }
 
     FieldNull(String name, String dbName, String table, String orgTable, int charsetIndex, int fieldLength, int decimals, long flags) {
         super(name, dbName, table, orgTable, charsetIndex, fieldLength, decimals, flags);